UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

Commission File Number 1-3473

TESORO CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code:

210-828-8484

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

None

      Indicate by check mark if the registrant is a well-known seasoned issuer as defined in Rule 405 of the Securities Act.    Yes þ         No o

      Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes o         No þ

      Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes þ         No o

      Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of the registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.    þ

      Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer þ                            Accelerated filer o                            Non-accelerated filer o

      Indicate by check mark whether the registrant is a shell company (as defined by Rule 12b-2 of the Act).    Yes o         No þ

      At June 30, 2005, the aggregate market value of the voting common stock held by non-affiliates of the registrant was approximately $3,217,903,000 based upon the closing price of its common stock on the New York Stock Exchange Composite tape. At March 1, 2006, there were 69,006,300 shares of the registrant’s common stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

      Portions of the registrant’s Proxy Statement to be filed pursuant to Regulation 14A pertaining to the 2006 Annual Meeting of Stockholders are incorporated by reference into Part III hereof. The Company intends to file such Proxy Statement no later than 120 days after the end of the fiscal year covered by this Form 10-K.

TESORO CORPORATION

ANNUAL REPORT ON FORM 10-K

TABLE OF CONTENTS

      This Annual Report on Form 10-K (including documents incorporated by reference herein) contains statements with respect to our expectations or beliefs as to future events. These types of statements are “forward-looking” and subject to uncertainties. See “Forward-Looking Statements” on page 46.

      When used in this Annual Report on Form 10-K, the terms “Tesoro”, “we”, “our” and “us”, except as otherwise indicated or as the context otherwise indicates, refer to Tesoro Corporation and its subsidiaries.

PART I

      We are one of the largest independent petroleum refiners and marketers in the United States with two operating segments — (1) refining crude oil and other feedstocks and selling petroleum products in bulk and wholesale markets (“refining”) and (2) selling motor fuels and convenience products in the retail market (“retail”). Through our refining segment, we produce refined products, primarily gasoline and gasoline blendstocks, jet fuel, diesel fuel and heavy fuel oils for sale to a wide variety of commercial customers in the western and mid-continental United States. Our retail segment distributes motor fuels through a network of gas stations, primarily under the Tesoro^® and Mirastar^® brands. See Notes C, D and O in our consolidated financial statements in Item 8 for additional information on our operating segments and properties.

      Tesoro is a Fortune 200 company based in San Antonio, Texas. We were incorporated in Delaware in 1968 under the name Tesoro Petroleum Corporation. On November 8, 2004, our name was changed to Tesoro Corporation. Our principal executive offices are located at 300 Concord Plaza Drive, San Antonio, Texas 78216-6999 and our telephone number is (210) 828-8484. Our website can be found at www.tsocorp.com. Our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and any amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 are made available through our website as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. You may receive a copy of our Annual Report on Form 10-K, including the financial statements, free of charge by writing to Tesoro Corporation, Attention: Investor Relations, 300 Concord Plaza Drive, San Antonio, Texas 78216-6999. We submitted to the New York Stock Exchange on June 14, 2005 our annual certification concerning corporate governance pursuant to Section 303A.12(a) of the New York Stock Exchange Listed Company Manual.

REFINING

      We own and operate six petroleum refineries, located in California (“California” region), Alaska and Washington (“Pacific Northwest” region), Hawaii (“Mid-Pacific” region) and North Dakota and Utah (“Mid-Continent” region), and sell refined products to a wide variety of customers in the western and mid-continental United States. Our refineries produce a high proportion of our refined product sales volumes, and we purchase the remainder from other refiners and suppliers. Our six refineries have a combined crude oil capacity of 563,000 barrels per day (“bpd”). We operate the largest refineries in Hawaii and Utah, the second largest refineries in northern California and Alaska, and the only refinery in North Dakota. Capacity and throughput rates of crude oil and other feedstocks by refinery are as follows:

      We experienced reduced throughput during scheduled refinery maintenance (“turnarounds”) at our California, Washington and Hawaii refineries in 2005, our California refinery in 2004 and our Alaska, North

Dakota and Utah refineries in 2003. We also reduced throughput rates at some of our refineries in late 2003 in response to regional and seasonal market conditions. Throughput exceeded our Washington refinery’s crude oil capacity in 2004 due to processing other feedstocks in addition to crude oil.

      Feedstock Supply. We purchase crude oil and other feedstocks for our refineries from a diversified supply of domestic and foreign sources through term agreements with renewal provisions and in the spot market. Prices under the term agreements generally fluctuate with market prices. We purchase approximately 75% of our crude oil under term contracts, which are primarily short-term agreements with market-related prices, and we purchase the remainder in the spot market. In 2005, we received 58% of our crude oil input from domestic sources (including 23% from Alaska’s North Slope) and 42% from foreign sources (including 12% from Canada). Approximately 50% of our total refining throughput was heavy crude oil in 2005 and 2004, compared with 58% in 2003. Heavy crude oil as a percent of total refining throughput was impacted during 2005, primarily due to scheduled turnarounds at our three largest refineries. The decrease in the heavy crude oil that we processed in 2004, as compared to 2003, was primarily due to scheduled and unscheduled downtime at our California refinery. We define “heavy” crude oil, which generally is sold at a discount to lighter crudes, as Alaska North Slope or crude oil with an American Petroleum Institute specific gravity of 32 degrees or less. Actual throughput volumes by feedstock type are summarized below (in thousand bpd):

      Refined Products. Refining yield represents production volumes of refined products consisting primarily of gasoline and gasoline blendstocks, jet fuel, diesel fuel and heavy fuel oils. We also manufacture other

products, including liquefied petroleum gas, petroleum coke and asphalt. Our refining yields, in volumes, are summarized below (in thousand bpd):

      Transportation and Terminals. To optimize the transportation of crude oil and refined products within our refinery system and secure shipping capacity, we term-charter four U.S. flag tankers and four foreign-flag tankers, seven of which are double-hulled and one of which is double-bottomed. Two of our U.S. flag term charters expire in 2010 and the remaining term charters expire between 2006 and 2009. We also charter several tugs and product barges for our Hawaii and Washington operations over varying terms ending in 2006 through 2010, with options to renew. Tesoro also has arrangements to transport crude oil in double-hulled

tankers from certain regions. Other tankers and ocean-going barges are also chartered on a short-term basis to transport crude oil and refined products. We also receive crude oils and ship refined products through Tesoro-owned and third-party pipelines as further described below.

      We operate refined product terminals at our refineries and at several other locations in California, Hawaii, Alaska, Washington and Idaho. We also distribute products through third-party terminals, truck racks and rail cars, which are supplied by our refineries and through purchases and exchange agreements with other refining and marketing companies.

      Refining. Our California refinery, located in Martinez on 2,206 acres about 30 miles east of San Francisco, is a highly complex refinery with a crude oil capacity of 166,000 bpd. We source our California refinery’s crude oil primarily from California, Alaska and foreign locations. Major product upgrading units at the refinery include fluid catalytic cracking (“FCC”), fluid coking, hydrocracking, naphtha reforming, vacuum distillation, hydrotreating and alkylation units. These units enable the refinery to produce a high proportion of motor fuels, including at least 90,000 bpd of cleaner-burning California Air Resources Board (“CARB”) gasoline and CARB diesel, as well as conventional gasoline and diesel. The refinery also produces heavy fuel oils, liquefied petroleum gas and petroleum coke. We have commenced a project at the refinery to modify the existing fluid coking unit into a delayed coking unit which is designed to (i) lower emissions as required by the Bay Area Quality Management District (see “Government Regulation and Legislation” for additional information) and (ii) increase overall efficiency by lowering operating costs. We anticipate this project will be completed in the fourth quarter of 2007.

      Transportation. Our California refinery has waterborne access through the San Francisco Bay that enables us to receive crude oil and ship products through our marine terminals. In addition, the refinery can receive crude oil through a third-party marine terminal at Martinez. We also receive California crude oils and ship refined products from the refinery through third-party pipeline systems.

      Terminals. We operate a refined product terminal at Stockton, California, and during the second quarter of 2005, we completed construction of a trucking product terminal at our California refinery. We also distribute products through third-party terminals and truck racks, which are supplied by our refinery and through purchases and exchange arrangements with other refining and marketing companies. We also lease approximately 500,000 barrels of storage capacity with waterborne access in southern California.

      Refining. Our Washington refinery, located in Anacortes on the Puget Sound on 917 acres about 60 miles north of Seattle, has a total crude oil capacity of 115,000 bpd. We source our Washington refinery’s crude oil primarily from Alaska, Canada and other foreign locations. The Washington refinery also processes intermediate feedstocks, primarily heavy vacuum gas oil, provided by some of our other refineries and by spot-market purchases from third-party refineries. Major product upgrading units at the refinery include the FCC, alkylation, hydrotreating, vacuum distillation, deasphalting and naphtha reforming units, which enable our Washington refinery to produce a high proportion of light products, such as gasoline (including CARB gasoline and components for CARB gasoline), diesel and jet fuel. The refinery also produces heavy fuel oils, liquefied petroleum gas and asphalt. During the 2005 fourth quarter, we completed construction of a wet gas scrubber to reduce air emissions from the FCC unit. In the 2006 first quarter, we will complete the installation of a 25,000 bpd diesel desulfurizer unit. We also have commenced a project to install a 25,000 bpd delayed coking unit which will allow our Washington refinery to process a larger proportion of lower-cost heavy crude oils and manufacture a larger percentage of higher-value products. We anticipate this project will be completed in the fourth quarter of 2007.

      Transportation. Our Washington refinery receives Canadian crude oil through a third-party pipeline originating in Edmonton, Alberta, Canada. We receive other crude oil through our Washington refinery’s

marine terminal. Our Washington refinery ships light products (gasoline, jet fuel and diesel) through a third-party pipeline system, which serves western Washington and Portland, Oregon. We also deliver gasoline and diesel fuel through a neighboring refinery’s truck rack and distribute diesel fuel through a truck rack at our refinery. We deliver refined products, including CARB gasoline and components for CARB gasoline, through our marine terminal to ships and barges and sell liquefied petroleum gas and asphalt at our refinery.

      Terminals. We operate refined product terminals at Anacortes, Port Angeles and Vancouver, Washington, supplied primarily by our Washington refinery. We also distribute products through third-party terminals and truck racks in our market areas, which are supplied by our refinery and through purchases and exchange arrangements with other refining and marketing companies.

      Refining. Our Alaska refinery is located near Kenai on the Cook Inlet on 488 acres approximately 70 miles southwest of Anchorage. Our Alaska refinery processes crude oil primarily from the Alaska Cook Inlet, Alaska North Slope and, to a lesser extent, foreign locations. The refinery has a total crude oil capacity of 72,000 bpd, and its product upgrading units include vacuum distillation, distillate hydrocracking, hydrotreating, naphtha reforming and light naphtha isomerization units. Our Alaska refinery produces gasoline and gasoline blendstocks, jet fuel, diesel fuel, heating oil, heavy fuel oils, liquefied petroleum gas and asphalt. We have commenced a project to install a 10,000 bpd diesel desulfurizer unit at the refinery, which will allow our Alaska refinery to manufacture additional quantities of low sulfur diesel to meet the increasing demand for cleaner fuels in Alaska. We anticipate this project will be completed in the second quarter of 2007.

      Transportation. We receive crude oil by tanker to the Alaska refinery through our marine terminal. Through our owned and operated 24-mile common-carrier crude pipeline, we also receive crude oil at our marine terminal, which is connected with some of the Cook Inlet oil fields. Our marine terminal is also used to load refined products on tankers and barges. We also own and operate a common-carrier petroleum products pipeline that runs from the Alaska refinery to our terminal facilities in Anchorage and to the Anchorage airport. This 71-mile pipeline has the capacity to transport approximately 40,000 bpd of products and allows us to transport gasoline, diesel and jet fuel to the terminal facilities, regardless of weather conditions. Both of our owned pipelines are subject to regulation by various federal, state and local agencies, including the Federal Energy Regulatory Commission (“FERC”).

      Terminals. We operate refined product terminals at Kenai and Anchorage, which are supplied by our Alaska refinery. We also distribute products through third-party terminals and truck racks in our market areas, which are supplied by our refinery and through purchases and exchange arrangements with other refining and marketing companies.

      Refining. Our 94,000 bpd Hawaii refinery is located at Kapolei on 131 acres about 22 miles west of Honolulu. We supply the Hawaii refinery with crude oil primarily from Southeast Asia, the Middle East and other foreign sources. Major product upgrading units include the vacuum distillation, hydrocracking, hydrotreating, visbreaking and naphtha reforming units. The Hawaii refinery produces gasoline and gasoline blendstocks, jet fuel, diesel fuel, heavy fuel oils, liquefied petroleum gas and asphalt.

      Transportation. We transport crude oil to Hawaii by tankers, which discharge through our single-point mooring terminal, 1.5 miles offshore from our refinery. Three underwater pipelines from the single-point mooring terminal allow crude oil and products to be transferred to and from the refinery’s storage tanks. We distribute refined products to customers on the island of Oahu through owned and third-party pipeline systems. Our product pipelines also connect the Hawaii refinery to Barbers Point Harbor, 2.5 miles away, where refined products are transferred to ships and barges.

      Terminals. We also distribute products from our refinery to customers through third-party terminals at Honolulu International Airport and Honolulu Harbor and by barge to Tesoro-owned and third-party terminal facilities on the islands of Oahu, Maui, Kauai and Hawaii.

      Refining. Our 58,000 bpd North Dakota refinery is located near Mandan on 960 acres. We supply our North Dakota refinery primarily with Williston Basin sweet crude oil. The refinery also can access other supplies, including Canadian crude oil. Major product upgrading units at the refinery include the FCC, naphtha reforming, hydrotreating and alkylation units. The North Dakota refinery produces gasoline, diesel fuel and jet fuel.

      Transportation. We own a crude oil pipeline system, consisting of over 700 miles of pipeline that delivers all of the crude oil supply to our North Dakota refinery. Our crude oil pipeline system receives crude oil from Canada and gathers crude oil from the Williston Basin and adjacent production areas in North Dakota and Montana and transports it to our refinery and has the capability to transport crude oil to other regional points where there is additional demand. Our crude oil pipeline system is a common carrier subject to regulation by various federal, state and local agencies, including the FERC. We distribute approximately 85% of our refinery’s production through a third-party product pipeline system which serves various areas from Bismarck, North Dakota to Minneapolis, Minnesota. All gasoline and distillate products from our refinery, with the exception of railroad-spec diesel fuel, can be shipped through that pipeline to third-party terminals.

      Terminals. We operate a refined products terminal at the North Dakota refinery. We also distribute products through a third-party product pipeline system which connects to third-party terminals located in North Dakota and Minnesota. We distribute products from our refinery to customers primarily through these third-party terminals.

      Refining. Our 58,000 bpd Utah refinery is located in Salt Lake City on 145 acres. Our Utah refinery processes crude oils primarily from Utah, Colorado, Wyoming and Canada. Major product upgrading units include the FCC, naphtha reforming, alkylation and hydrotreating units. The Utah refinery produces gasoline, diesel fuel and jet fuel.

      Transportation. Our Utah refinery receives crude oil primarily by third-party pipelines originating from fields in Utah, Colorado, Wyoming and Canada. We distribute the refinery’s production through a system of both owned and third-party terminals and third-party pipeline connections, primarily in Utah, Idaho and eastern Washington, with some product delivered in Nevada and Wyoming.

      Terminals. In addition to sales at the refinery, we distribute products to customers through a third-party pipeline to the two terminals we own at Boise and Burley, Idaho and to third-party terminals in Pocatello, Idaho and Pasco, Washington.

      We sell refined products including gasoline and gasoline blendstocks, jet fuel, diesel fuel, heavy oil and residual products in both the bulk and wholesale markets. The majority of our wholesale volumes are sold in 9 states to unbranded distributors, which are retail stations owned by third parties that sell products purchased through Tesoro owned and third-party terminals and truck racks. Our bulk volumes are primarily sold to major oil companies, electric power producers, railroads, airlines and marine and industrial end-users. In addition, we sell products that we manufacture and products purchased or received on exchange from third parties. Exchange agreements provide for the delivery of Tesoro’s refined products primarily to third-party terminals in exchange for the delivery of refined products from the third parties at specific locations. These arrangements

help to optimize our refinery supply requirements and lower transportation costs. Our refined product sales, including intersegment sales to our retail operations, consisted of:

      Gasoline and Gasoline Blendstocks. We sell gasoline and gasoline blendstocks in both the bulk and wholesale markets in the western and mid-continental United States. The demand for gasoline is seasonal in many of our markets, with lowest demand during the winter months. We also sell gasoline to wholesale customers and bulk end-users (including several major oil companies) under various supply agreements. Gasoline also is delivered to refiners and marketers in exchange for product received at other locations in our markets. We sell, at wholesale, to unbranded distributors and high-volume retailers, and we distribute product through Tesoro-owned and third-party terminals and truck racks.

      Jet Fuel. We supply commercial jet fuel to passenger and cargo airlines at airports in Alaska, Hawaii, California, Washington, Utah and other western states. We also supply jet fuel to the U.S. military in certain of our markets.

      Diesel Fuel. We sell our diesel fuel production primarily on a wholesale basis for marine, transportation, industrial and agricultural use, as well as for home heating. We sell lesser amounts to end-users through marine terminals and for power generation in Hawaii and Washington. Diesel fuel production by refiners in our market areas is generally in balance with demand. As a result of variations in seasonal demand, we ship diesel fuel to or from our Alaska and Hawaii operations.

      Heavy Fuel Oils and Residual Products. We sell heavy fuel oils to other refineries, electric power producers and marine and industrial end-users. Our refineries supply substantially all of the marine fuels that we sell through leased facilities at Port Angeles and Seattle, Washington, and Portland, Oregon, and through owned and leased facilities in Alaska and Hawaii. We sell our asphalt for paving materials in Hawaii, Alaska and Washington. In Alaska and the Pacific Northwest, demand for asphalt is seasonal because mild weather conditions are needed for highway construction. Our California refinery produces petroleum coke that we sell to industrial end-users.

      Sales of Purchased Products. In the normal course of business to meet local market demands, we purchase refined products manufactured by others for resale to our customers. We purchase these products, primarily gasoline, jet fuel, diesel fuel and industrial and marine fuel blendstocks, mainly in the spot market. We conduct our gasoline and diesel fuel purchase and resale activity primarily on the U.S. West Coast. Our jet fuel activity primarily consists of supplying markets in Alaska, California and Hawaii. We also purchase a lesser amount of gasoline and other products that are sold outside of our refineries’ local markets.

RETAIL

      Through our network of retail stations, we sell gasoline and diesel fuel in the western and mid-continental United States. The demand for gasoline is seasonal in a majority of our markets, with highest demand for gasoline during the summer driving season. We sell gasoline and diesel to retail customers through company-operated sites and agreements with third-party branded distributors (or “jobber/dealers”). As of December 31, 2005, our retail segment included a network of 478 branded retail stations (under the Tesoro^® and Mirastar^® brands), comprising 210 company-operated retail gasoline stations and 268 jobber/dealer stations. Our retail network provides a committed outlet for a portion of the motor fuels produced by our refineries.

Most of our company-operated Tesoro^®stations include 2-Go Tesoro^® brand convenience stores that sell a wide variety of merchandise items. The following table summarizes our retail operations:

COMPETITION AND OTHER

      The petroleum industry is highly competitive in all phases, including the purchase of crude oil and the marketing of refined petroleum products. The industry also competes with other industries that supply the

energy and fuel requirements of industrial, commercial and individual consumers. In recent years, consolidation in the refining and marketing industry has reduced the number of competitors; however, it has not reduced overall competition. We compete with a number of major integrated oil companies and other companies that have greater financial and other resources. These competitors have a greater ability to bear the economic risks inherent in all phases of the industry. In addition, unlike many of our competitors, we do not produce crude oil for use in our refining operations, and we are not as large as many of our competitors who may have a competitive advantage when negotiating with crude oil producers.

      Our California and Washington refineries compete with several refineries on the U.S. West Coast, including refineries that have greater economies of scale. Our Hawaii refinery competes primarily with one other refinery in Hawaii, owned by a major integrated oil company, that also is located at Kapolei and has a crude oil capacity of 54,000 bpd. Historically, the other refinery produces lower volumes of jet fuel than our Hawaii refinery. The Alaska refinery competes primarily with other refineries in Alaska and on the U.S. West Coast. Our refining competition in Alaska includes two refineries near Fairbanks and a refinery near Valdez. We estimate that the other Alaska refineries have a combined capacity to process approximately 270,000 bpd of crude oil. After processing Alaska North Slope crude oil and removing the higher-value products, these refiners are permitted, because of their direct connection to the Trans Alaska Pipeline System, to return the remainder of the processed crude oil into the pipeline system as “return oil” in consideration for a fee, thereby eliminating their need to transport and market lower-value products that are not in demand in Alaska. Our Alaska refinery is not connected to the Trans Alaska Pipeline System, and we, therefore, cannot return our lower-value products to that pipeline system. Our North Dakota refinery is the only refinery in North Dakota. Refineries in Wyoming, Montana, the Midwest and the United States Gulf Coast region are the primary competitors with our North Dakota refinery. Our Utah refinery is the largest of five refineries located in Utah. We estimate that these other refineries have a combined capacity to process approximately 107,500 bpd of crude oil. These five refineries collectively supply a high proportion of the gasoline and distillate products consumed in the states of Utah and Idaho, with additional supplies provided from refineries in surrounding states. Our California, Washington, Hawaii and Alaska refineries also compete with companies that import refined products from other parts of the world, including the Far East.

      Our jet fuel sales in Alaska are concentrated in Anchorage, where we are one of the principal suppliers to the Anchorage International Airport, a major hub for air cargo traffic between manufacturing regions in the Far East and markets in the United States and Europe. In Hawaii, jet fuel sales are concentrated in Honolulu, where we are the principal supplier to the Honolulu International Airport. We also serve four airports on other islands in Hawaii. In Washington, jet fuel sales are concentrated at the Seattle/ Tacoma International Airport. We also supply jet fuel to customers in Portland, Oregon; Los Angeles, San Francisco and San Diego, California; Las Vegas and Reno, Nevada; and Phoenix, Arizona. Other refiners and marketers compete for sales at all of these airports. In Utah, our jet fuel sales are concentrated in Salt Lake City, and we also supply jet fuel to customers in Boise, Burley and Pocatello, Idaho. The North Dakota refinery supplies jet fuel to customers in Minneapolis/ St. Paul and Moorhead, Minnesota and in Bismarck and Jamestown, North Dakota. We compete with other suppliers for U.S. military contracts in Alaska, Hawaii and North Dakota. Both the Alaska and Hawaii markets periodically require additional jet fuel supplies from outside the state to meet demand.

      We sell our diesel fuel production primarily on a wholesale basis, competing with other refiners and marketers in all of our market areas. Refined products from foreign sources, including Canada, also compete for distillate customers in our market areas.

      We sell gasoline in Alaska, California, Hawaii, North Dakota, Utah, Washington and other western and mid-continental states through a network of company-operated retail stations and branded and unbranded jobber/dealers. Competitive factors that affect retail marketing include price, station appearance, location and brand awareness. Our retail marketing operations compete with other independent marketing companies, integrated oil companies and high-volume retailers.

GOVERNMENT REGULATION AND LEGISLATION

      All of our operations, like those of other companies engaged in similar businesses, are subject to extensive and frequently changing federal, state, regional and local laws, regulations and ordinances relating to the protection of the environment, including those governing emissions or discharges to the air and water, the handling and disposal of solid and hazardous wastes and the remediation of contamination. While we believe our facilities are in substantial compliance with current requirements, our facilities will continue during 2006 and over the next several years to be engaged in meeting new requirements promulgated by the U.S. Environmental Protection Agency (“EPA”) and the states and local jurisdictions in which we operate as described below.

      Changes in fuel manufacturing standards, including those related to gasoline and diesel fuel sulfur concentrations, also affect our operations. EPA regulations related to the Clean Air Act require reductions in the sulfur content in gasoline. To meet the revised gasoline standard, we spent $28 million in 2005. Our California, Washington, Hawaii, Alaska and North Dakota refineries will not require additional capital spending to meet the low sulfur gasoline standards. We currently estimate we will make additional capital improvements of approximately $8 million at our Utah refinery from 2008 through 2009, that will permit the Utah refinery to produce gasoline meeting the sulfur limits imposed by the EPA.

      EPA regulations related to the Clean Air Act also require reductions in the sulfur content in diesel fuel manufactured for on-road consumption. In general, the new on-road diesel fuel standards will become effective on June 1, 2006. In May 2004, the EPA issued a rule regarding the sulfur content of non-road diesel fuel. The requirements to reduce non-road diesel sulfur content will become effective in phases between 2007 and 2010. We spent $46 million in 2005 to meet the revised diesel fuel standards, and based on our latest engineering estimates, we expect to spend approximately $71 million in capital improvements through 2007. Included in the estimate are capital projects to manufacture additional quantities of low sulfur diesel at our Alaska refinery, for which we expect to spend approximately $53 million through 2007. These cost estimates are subject to further review and analysis. Our California, Washington and North Dakota refineries will not require additional capital spending to meet the new non-road diesel fuel standards.

      We expect to spend approximately $1 million in capital improvements in 2006 at our Washington refinery to comply with the Maximum Achievable Control Technologies standard for petroleum refineries (“Refinery MACT II”). We spent approximately $17 million during 2005.

      In connection with our 2001 acquisition of our North Dakota and Utah refineries, we assumed the sellers’ obligations and liabilities under a consent decree among the United States, BP Exploration and Oil Co. (“BP”), Amoco Oil Company and Atlantic Richfield Company. BP entered into this consent decree for both the North Dakota and Utah refineries for various alleged violations. As the owner of these refineries, we are required to address issues, that include leak detection and repair, flaring protection and sulfur recovery unit optimization. We currently estimate that we will spend $5 million over the next three years to comply with this consent decree. We also agreed to indemnify the sellers for all losses of any kind incurred in connection with the consent decree.

      In connection with the 2002 acquisition of our California refinery, subject to certain conditions, we assumed the seller’s obligations pursuant to settlement efforts with the EPA concerning the Section 114 refinery enforcement initiative under the Clean Air Act, except for any potential monetary penalties, which the seller retains. In November 2005, the Consent Decree was entered by the District Court for the Western District of Texas in which we agreed to undertake projects at our California refinery to reduce air emissions. We spent $2 million in 2005, and we currently estimate we will make additional capital improvements of approximately $30 million through 2010 to satisfy the requirements of the Consent Decree. This cost estimate is subject to further review and analysis.

      During the fourth quarter of 2005, we received approval by the Hearing Board for the Bay Area Air Quality Management District to modify our existing fluid coker unit to a delayed coker at our California refinery which is designed to (i) lower emissions and (ii) increase overall efficiency by lowering operating

costs. We negotiated the terms and conditions of the Second Conditional Abatement Order with the District in response to the January 2005 mechanical failure of one of our boilers at the California refinery. We spent $3 million during 2005 for this project, and we currently estimate that we will spend approximately $272 million through the fourth quarter of 2007. This cost estimate is subject to further review and analysis.

      We will spend additional capital at the California refinery for reconfiguring and replacing above-ground storage tank systems and upgrading piping within the refinery. We spent $15 million in 2005 for these related projects at our California refinery, and we currently estimate that we will make additional capital improvements of approximately $109 million through 2010. This cost estimate is subject to further review and analysis.

      Conditions may develop that cause increases or decreases in future expenditures for our various sites, including, but not limited to, our refineries, tank farms, retail gasoline stations (operating and closed locations) and petroleum product terminals, and for compliance with the Clean Air Act and other federal, state and local requirements. We cannot currently determine the amounts of such future expenditures.

      We operate in environmentally sensitive coastal waters, where tanker, pipeline and refined product transportation operations are closely regulated by federal, state and local agencies and monitored by environmental interest groups. The transportation of crude oil and refined product over water involves risk and subjects us to the provisions of the Federal Oil Pollution Act of 1990 and related state regulations, which require that most oil refining, transport and storage companies maintain and update various oil spill prevention and oil spill contingency plans. We have submitted these plans and received federal and state approvals necessary to comply with the Federal Oil Pollution Act of 1990 and related regulations. Our oil spill prevention plans and procedures are frequently reviewed and modified to prevent oil and product releases and to minimize potential impacts should a release occur.

      We currently charter tankers to ship crude oil from foreign and domestic sources to our California, Mid-Pacific and Pacific Northwest refineries. The Federal Oil Pollution Act of 1990 requires, as a condition of operation, that we demonstrate the capability to respond to the “worst case discharge” to the maximum extent practicable. As an example, the State of Alaska requires us to provide spill-response capability to contain or control and cleanup amounts equal to 50,000 barrels of crude oil for a tanker carrying fewer than 500,000 barrels and 300,000 barrels for a tanker carrying more than 500,000 barrels. To meet these requirements, we have entered into contracts with various parties to provide spill response services. We have entered into spill-response agreements with (1) Cook Inlet Spill Prevention and Response, Incorporated (for which we fund approximately 79% of expenditures) and Alyeska Pipeline Service Company for spill-response services in Alaska and (2) Clean Islands Council for response services throughout the State of Hawaii. In addition, for larger spill contingency capabilities, we have entered into contracts with Marine Spill Response Corporation for Hawaii, the San Francisco Bay and Puget Sound. We believe these contracts, and those with other regional spill-response organizations that are in place on a location by location basis, provide the additional services necessary to meet spill-response requirements established by state and federal law.

      Our crude oil pipeline system in North Dakota and our pipeline systems in Alaska are common carriers subject to regulation by various federal, state and local agencies, including the FERC under the Interstate Commerce Act. The Interstate Commerce Act provides that, to be lawful, the rates of common carrier petroleum pipelines must be “just and reasonable” and not unduly discriminatory.

      The intrastate operations of our crude oil pipeline system are subject to regulation by the North Dakota Public Services Commission. The intrastate operations of our Alaska pipelines are subject to regulation by the Regulatory Commission of Alaska. Like the FERC, the state regulatory authorities require that we notify shippers of proposed intrastate tariff increases and they have an opportunity to protest the increases. The North Dakota Public Services Commission also files with the state authorities copies of interstate tariff charges filed with the FERC. In addition to challenges to new or proposed rates, challenges to intrastate rates

that have already become effective are permitted by complaint of an interested person or by independent action of the appropriate regulatory authority.

EMPLOYEES

      At December 31, 2005, we had approximately 3,928 full-time employees. Approximately 1,225 of our employees are covered by collective bargaining agreements with terms expiring on January 31, 2009. During the 2005 first quarter, we extended the collective bargaining agreements which were previously set to expire on January 31, 2006. We consider our relations with our employees to be satisfactory.

PROPERTIES

      Our principal properties are described above under the captions “Refining” and “Retail”. In addition, we own feedstock and refined product storage facilities at our refinery and terminal locations. We believe that our properties and facilities are generally adequate for our operations and that our facilities are maintained in a good state of repair. We are the lessee under a number of cancelable and non-cancelable leases for certain properties, including office facilities, retail facilities, ship charters and equipment used in the storage, transportation and production of feedstocks and refined products. See Notes E and O in our consolidated financial statements in Item 8.

      We conduct our retail business under the Tesoro^®, Tesoro Alaska^®, Mirastar^®, and 2-Go Tesoro^® brands. Our retail marketing system under these brands includes 478 branded retail stations, of which 210 are company-operated.

EXECUTIVE OFFICERS OF THE REGISTRANT

      The following is a list of the Company’s executive officers, their ages and their positions with the Company at March 1, 2006.

      There are no family relationships among the officers listed, and there are no arrangements or understandings pursuant to which any of them were elected as officers. Officers are elected annually by our Board of Directors at their first meeting following the annual meeting of stockholders. The term of each office runs until the corresponding meeting of the Board of Directors in the next year or until a successor has been elected or qualified.

      Tesoro’s executive officers have been employed by Tesoro or its subsidiaries in an executive capacity for at least the past five years, except for those named below who have had the business experience indicated during that period. Positions, unless otherwise specified, are with Tesoro.

      William J. Finnerty was named Executive Vice President and Chief Operating Officer in February 2006. Prior to that, he served as Executive Vice President, Operations beginning in January 2005 and Senior Vice President, Supply and Distribution of Tesoro Refining and Marketing Company beginning in February 2004. He joined Tesoro in December 2003 as Vice President, Crude Oil and Logistics, of Tesoro Refining and Marketing Company. Prior to joining Tesoro, Mr. Finnerty served as Vice President, Trading North America Crude, for ChevronTexaco from October 2001 to November 2003. From May 2001 to October 2001, he served as Vice President, Texaco Oil Trading and Transport Company. From June 2000 to May 2001, Mr. Finnerty was Senior Vice President, Trading and Operations for Equiva Trading Company.

      Everett D. Lewis was named Executive Vice President, Strategic Planning in January 2005. Prior to that, he served as Senior Vice President, Corporate Strategic Planning beginning in November 2004. Mr. Lewis served as Senior Vice President, Planning and Optimization from February 2003 to November 2004 and Senior Vice President, Planning and Risk Management from April 2001 to February 2003. He served as Senior Vice President of Strategic Projects from March 1999 to April 2001.

      W. Eugene Burden was named Senior Vice President, Government Affairs in February 2006. Prior to that, he served as Senior Vice President, External Affairs from November 2004 to February 2006, Senior Vice President, Human Resources and Government Relations from June 2002 to November 2004, President of Tesoro Alaska Company from February 2001 to June 2002, and Senior Vice President and President, Northwest Region of Tesoro Refining and Marketing Company from September 2001 until June 2002. Mr. Burden served as Senior Vice President, Government Relations of Tesoro Petroleum Companies, Inc. from September 1999 to February 2001.

      Claude A. Flagg was named Senior Vice President, Supply and Optimization in February 2005. He joined Tesoro in January 2005 as Senior Vice President, Planning and Optimization. Prior to joining Tesoro, he served as General Manager of Supply Optimization at Shell Oil Products U.S. from January 2003 to December 2004. From May 2002 to January 2003, Mr. Flagg was General Manager of Supply Optimization at Equilon Enterprises, LLC. He was General Manager of Equilon Enterprises, LLC’s Bay/Valley Refining Complex from April 1999 to May 2002.

      J. William Haywood was named Senior Vice President, Refining in March 2005. He joined Tesoro in May 2002 as Senior Vice President and also became President of the California Region of Tesoro Refining and Marketing Company in September 2002. Prior to joining Tesoro, Mr. Haywood served as Regional Vice President of Ultramar Diamond Shamrock Corporation, responsible for California refineries from September 2000 to May 2002.

      Joseph M. Monroe was named Senior Vice President, Corporate Development in February 2006. Prior to that, he served as Senior Vice President, Business Integration and Analysis beginning in February 2005. From November 2004 to February 2005, he served as Senior Vice President, Organizational Effectiveness. From February 2004 to November 2004, he served as Senior Vice President, Strategic Planning and Business Development of Tesoro Petroleum Companies, Inc. From May 2002 to February 2004, Mr. Monroe served as Senior Vice President, Supply and Distribution, of Tesoro Refining and Marketing Company. Prior to joining Tesoro, he was Vice President, Pipelines and Terminals of Unocal Corporation and President of Unocal Pipeline Company from January 1999 through May 2002.

      Daniel J. Porter was named Senior Vice President, Marketing in April 2005. Prior to that, he served as President of the Northwest Region of Tesoro Refining and Marketing Company and Anacortes Refinery Manager from June 2002 to April 2005. He was also President of the Northern Great Plains Region and Mandan Refinery Manager from September 2001 to June 2002. Prior to joining Tesoro, Mr. Porter served as Business Unit Leader of BP’s North Dakota refinery from January 1999 to September 2001.

      Susan A. Lerette was named Vice President, Human Resources in May 2005. Prior to that, she served as Vice President, Human Resources and Communications from May 2004 to May 2005. From April 2001 to May 2004, she served as Vice President, Communications. She was Director, Investor Relations from April 1999 to April 2001.

      Charles S. Parrish was named Vice President, General Counsel and Secretary in March 2005. Prior to that, he served as Vice President, Assistant General Counsel and Secretary beginning in November 2004. Mr. Parrish served as Vice President, Assistant General Counsel of Tesoro Petroleum Companies, Inc. from March 2003 to November 2004. From 1995 through March 2003, he served numerous roles in the Company’s legal department, primarily focused on matters related to the Company’s capital structure and Securities Act reporting.

      Otto C. Schwethelm was named Vice President and Controller in February 2003. From September 2002 to February 2003, Mr. Schwethelm served as Vice President and Operations Controller. Prior to that, he served as Vice President, Shared Services of Tesoro Petroleum Companies, Inc. from December 2001 to September 2002. From November 1999 to December 2001, Mr. Schwethelm was Vice President, Development and Business Analysis.

      Sarah S. Simpson was named Vice President of Corporate Communications in June 2005. Prior to joining Tesoro, she served as Director of Corporate Communications and Community Relations at Cemex, Inc. from November 2004 to June 2005 From July 2000 to November 2004, she served as Director of Corporate Communications at Waste Management, Inc.

      G. Scott Spendlove has served as Vice President, Finance and Treasurer since May 2003 and as Vice President, Finance from January 2002 to May 2003. Prior to joining Tesoro in 2002, he served as Vice President, Corporate Planning and Investor Relations of Ultramar Diamond Shamrock Corporation from December 1999 to December 2001.

BOARD OF DIRECTORS OF THE REGISTRANT

      The following is a list of the Company’s Board of Directors:

The volatility of crude oil prices, refined product prices and natural gas and electrical power prices may have a material adverse effect on our cash flow and results of operations.

      Our earnings and cash flows from our refining and wholesale marketing operations depend on a number of factors, including fixed and variable expenses (including the cost of refinery feedstocks) and the margin above those expenses at which we are able to sell refined products. In recent years, the prices of crude oil and refined products have fluctuated substantially. These prices depend on numerous factors beyond our control, including the demand for crude oil, gasoline and other refined products, which are subject to, among other things:

      Prices for refined products are influenced by the price of crude oil. We do not produce crude oil and must purchase all of our crude oil, the price of which fluctuates on worldwide market conditions. Generally, an increase or decrease in the price of crude oil affects the price of gasoline and other refined products. However, the prices for crude oil and prices for our refined products can fluctuate in different directions based on worldwide market conditions. In addition, the timing of the relative movement of the prices, as well as the overall change in product prices, can reduce profit margins and could have a significant impact on our refining and wholesale marketing operations, earnings and cash flow. Also, crude oil supply contracts are generally term contracts with market-responsive pricing provisions. We purchase our refinery feedstocks before manufacturing and selling the refined products. Price level changes during the period between purchasing feedstocks and selling the manufactured refined products from these feedstocks could have a significant effect on our financial results. We also purchase refined products manufactured by others for sale to our customers. Price level changes during the periods between purchasing and selling these products also could have a material adverse effect on our business, financial condition and results of operations.

      Volatile prices for natural gas and electrical power used by our refineries and other operations have affected manufacturing and operating costs. Natural gas and electricity prices have been and will continue to be affected by supply and demand for fuel and utility services in both local and regional markets.

Our business is impacted by risks inherent in petroleum refining operations.

      The operation of refineries, pipelines and product terminals is inherently subject to spills, discharges or other releases of petroleum or hazardous substances. If any of these events had previously occurred or occurs

in the future in connection with any of our refineries, pipelines or product terminals, or in connection with any facilities to which we sent wastes or by-products for treatment or disposal, other than events for which we are indemnified, we could be liable for all costs and penalties associated with their remediation under federal, state and local environmental laws or common law, and could be liable for property damage to third parties caused by contamination from releases and spills. The penalties and clean-up costs that we may have to pay for releases or spills, or the amounts that we may have to pay to third parties for damage to their property, could be significant and the payment of these amounts could have a material adverse effect on our business, financial condition and results of operations.

      We operate in environmentally sensitive coastal waters, where tanker, pipeline and refined product transportation operations are closely regulated by federal, state and local agencies and monitored by environmental interest groups. Our California, Mid-Pacific and Pacific Northwest refineries import crude oil feedstocks by tanker. Transportation of crude oil and refined products over water involves inherent risk and subjects us to the provisions of the Federal Oil Pollution Act of 1990 and state laws in California, Hawaii, Washington and Alaska. Among other things, these laws require us to demonstrate in some situations our capacity to respond to a “worst case discharge” to the maximum extent possible. We have contracted with various spill response service companies in the areas in which we transport crude oil and refined products to meet the requirements of the Federal Oil Pollution Act of 1990 and state laws. However, there may be accidents involving tankers transporting crude oil or refined products, and response services may not respond to a “worst case discharge” in a manner that will adequately contain that discharge, or we may be subject to liability in connection with a discharge.

The dangers inherent in our operations and the potential limits on insurance coverage could expose us to potentially significant liability costs.

      Our operations are subject to hazards and risks inherent in refining operations and in transporting and storing crude oil and refined products, such as fires, natural disasters, explosions, pipeline ruptures and spills and mechanical failure of equipment at our or third-party facilities, any of which can result in personal injury claims and other damage to our properties and the properties of others. In addition, we operate six petroleum refineries, any of which could experience a major accident, be damaged by severe weather or other natural disaster, or otherwise be forced to shut down. Any such unplanned shutdown could have a material adverse effect on our business, financial condition and results of operations. While we carry property, casualty and business interruption insurance, we do not maintain insurance coverage against all potential losses, and we could suffer losses for uninsurable or uninsured risks or in amounts in excess of existing insurance coverage. The occurrence of an event that is not fully covered by insurance could have a material adverse effect on our business, financial condition and results of operations.

Our operations are subject to general environmental risks, expenses and liabilities which could affect our results of operations.

      From time to time we have been, and presently are, subject to litigation and investigations with respect to environmental and related matters, including product liability claims related to the oxygenate MTBE. We may become involved in further litigation or other proceedings, or we may be held responsible in any existing or future litigation or proceedings, the costs of which could be material.

      We have in the past operated service stations with underground storage tanks in various jurisdictions, and currently operate service stations that have underground storage tanks in 18 states in the mid-continental and western United States. Federal and state regulations and legislation govern the storage tanks, and compliance with these requirements can be costly. The operation of underground storage tanks also poses certain other risks, including damages associated with soil and groundwater contamination. Leaks from underground storage tanks which may occur at one or more of our service stations, or which may have occurred at our previously operated service stations, may impact soil or groundwater and could result in fines or civil liability for us.

      Consistent with the experience of other U.S. refineries, environmental laws and regulations have raised operating costs and require significant capital investments at our refineries. We believe that existing physical facilities at our refineries are substantially adequate to maintain compliance with existing applicable laws and regulatory requirements. However, potentially material expenditures could be required in the future. For example, we may be required to comply with evolving environmental, health and safety laws, regulations or requirements that may be adopted or imposed in the future. We also may be required to address information or conditions that may be discovered in the future and that require a response.

We are subject to interruptions of supply and increased costs as a result of our reliance on third-party transportation of crude oil and refined products.

      Our Washington refinery receives all of its Canadian crude oil and delivers a high proportion of its gasoline, diesel and jet fuel through third-party pipelines. Our Hawaii and Alaska refineries receive most of their crude oil and transport a substantial portion of refined products through ships and barges. Our Utah refinery receives substantially all of its crude oil and delivers substantially all of its products through third-party pipelines. Our North Dakota refinery delivers substantially all of its products through a third-party pipeline system. Our California refinery receives approximately one-third of its crude oil through pipelines and the balance through marine vessels. Substantially all of our California refinery’s production is delivered through third-party pipelines, ships and barges. In addition to environmental risks discussed above, we could experience an interruption of supply or an increased cost to deliver refined products to market if the ability of the pipelines or vessels to transport crude oil or refined products is upset because of accidents, governmental regulation or third-party action. A prolonged upset of the ability of a pipeline or vessels to transport crude oil or product could have a material adverse effect on our business, financial condition and results of operations.

Terrorist attacks and threats or actual war may negatively impact our business.

      Our business is affected by general economic conditions and fluctuations in consumer confidence and spending, which can decline as a result of numerous factors outside of our control, such as actual or threatened terrorist attacks and acts of war. Terrorist attacks, as well as events occurring in response to or in connection with them, including future terrorist attacks against U.S. targets, rumors or threats of war, actual conflicts involving the United States or its allies, or military or trade disruptions impacting our suppliers or our customers or energy markets generally, may adversely impact our operations. As a result, there could be delays or losses in the delivery of supplies and raw materials to us, delays in our delivery of refined products, decreased sales of our products and extension of time for payment of accounts receivable from our customers. Strategic targets such as energy-related assets (which could include refineries such as ours) may be at greater risk of future terrorist attacks than other targets in the United States. These occurrences could significantly impact energy prices, including prices for our crude oil and refined products, and have a material adverse impact on the margins from our refining and wholesale marketing operations. In addition, disruption or significant increases in energy prices could result in government-imposed price controls. Any one of, or a combination of, these occurrences could have a material adverse effect on our business, financial condition and results of operations.

Our operating results are seasonal and generally are lower in the first and fourth quarters of the year.

      Demand for gasoline is higher during the spring and summer months than during the winter months in most of our markets due to seasonal increases in highway traffic. As a result, our operating results for the first and fourth quarters are generally lower than for those in the second and third quarters.

      None.

      In the ordinary course of business, we become party to or otherwise involved in lawsuits, administrative proceedings and governmental investigations, including environmental, regulatory and other matters. Large and sometimes unspecified damages or penalties may be sought from us in some matters and some matters may require years for us to resolve. We cannot provide assurance that an adverse resolution of one or more of the matters described below during a future reporting period will not have a material adverse effect on our financial position or results of operations in future periods. However, on the basis of existing information, we believe that the resolution of these matters, individually or in the aggregate, will not have a material adverse effect on our financial position or results of operations.

      In November 2003, we filed suit in Contra Costa County Superior Court against Tosco alleging that Tosco misrepresented, concealed and failed to disclose certain additional environmental conditions at our California refinery. The court granted Tosco’s motion to compel arbitration of our claims for these certain additional environmental conditions. In the arbitration proceedings we initiated against Tosco in December 2003, we are also seeking a determination that Tosco is liable for investigation and remediation of these certain additional environmental conditions, the amount of which is currently unknown and therefore a reserve has not been established, and which may not be covered by the $50 million indemnity for the defined environmental liabilities arising from pre-acquisition operations. In response to our arbitration claims, Tosco filed counterclaims in the Contra Costa County Superior Court action alleging that we are contractually responsible for additional environmental liabilities at our California refinery, including the defined environmental liabilities arising from pre-acquisition operations. In February 2005, the parties agreed to stay the arbitration proceedings to pursue settlement discussions. In June 2005, the parties agreed in principle to settle their claims, including the defined environmental liabilities arising from pre-acquisition operations and certain additional environmental conditions, pending negotiation and execution of a final written settlement agreement. In the event we are unable to finalize the settlement, we intend to vigorously prosecute our claims against Tosco and to oppose Tosco’s claims against us, although we cannot provide assurance that we will prevail. For further information related to the claims, see Note O in our consolidated financial statements in Item 8.

      During the fourth quarter of 2005, we received approval by the Hearing Board for the Bay Area Air Quality Management District to modify our existing fluid coker unit to a delayed coker at our California refinery. We negotiated the terms and conditions of the Second Conditional Abatement Order with the District in response to the January 2005 mechanical failure of one of our boilers at the California refinery. We also received two notices of violation (“NOV”) from the Bay Area Air Quality Management District as a result of the January 2005 mechanical failure. On January 26, 2006, we entered into a Settlement Agreement and Release with the District and the District Attorney of Contra Costa County, California. In exchange for the release of allegations based upon certain air quality emission limits and provisions of the California Health and Safety Code, we paid a civil penalty of $1.1 million.

      As previously disclosed, we were a defendant, along with other manufacturing, supply and marketing defendants, in ten pending cases alleging MTBE contamination in groundwater. During the 2005 fourth quarter, we were named as a defendant in one additional case. The defendants are being sued for having manufactured MTBE and having manufactured, supplied and distributed gasoline containing MTBE. The plaintiffs in each of the 11 pending cases, all in California, are generally water providers, governmental authorities and private well owners alleging that, in part, the defendants are liable for manufacturing or distributing a defective product. The suits generally seek individual, unquantified compensatory and punitive damages and attorney’s fees, but we cannot estimate the amount or likelihood of the ultimate resolution of these matters at this time, and accordingly, we have not established a reserve for these cases. We believe we have defenses to these claims and intend to vigorously defend the lawsuits.

      On October 24, 2005, we received an NOV from the EPA. The EPA alleges certain modifications made to the fluid catalytic cracking unit at our Washington refinery prior to our acquisition of the refinery were made without a permit in violation of the Clean Air Act. We are investigating the allegations and believe the

ultimate resolution of the NOV will not have a material adverse effect on our financial position or results of operations.

      During the first quarter of 2005, we negotiated a settlement of 70 NOVs from the Bay Area Air Quality Management District. The NOVs alleged various violations of air quality requirements at the California refinery between June 2002 and February 2004. We paid a civil penalty of $575,000 to resolve the matter.

      On February 28, 2006, we received an offer of settlement from the Bay Area Air Quality Management District. The District has offered to settle 28 NOVs issued to Tesoro from January 2004 to September 2004 for $275,000. The NOVs allege violations of various air quality requirements at the California refinery.

      As previously reported, during the first quarter of 2005 we began settlement discussions with the California Air Resources Board (“CARB”) concerning an NOV we received in October 2004. The NOV, issued by CARB, alleges we offered for sale eleven batches of gasoline in California that did not meet CARB’s gasoline exhaust emission limits. In January 2006, we executed a Settlement Agreement and Release with CARB which requires us to pay a civil penalty of $325,000 to resolve this matter.

      None.

PART II

      Our common stock is listed under the symbol “TSO” on the New York Stock Exchange and the Pacific Exchange. Summarized below are high and low sales prices of and dividends declared on our common stock on the New York Stock Exchange during 2005 and 2004. Quarterly cash dividends have been declared for each quarter beginning in June 2005. Prior to June 2005, we had not paid dividends on our common stock since 1986.

      On February 2, 2006, our Board of Directors declared a quarterly cash dividend on common stock of $0.10 per share, payable on March 15, 2006 to shareholders of record on March 1, 2006. At March 1, 2006, there were approximately 1,978 holders of record of our 69,006,300 outstanding shares of common stock. For information regarding restrictions on future dividend payments and stock repurchases, see Management’s Discussion and Analysis of Financial Condition and Results of Operations in Item 7 and Notes E and F in our consolidated financial statements in Item 8.

      The 2006 annual meeting of stockholders will be held at 8:00 A.M. Pacific Daylight Time on Wednesday, May 3, 2006, at The Four Seasons Hotel, 757 Market Street, San Francisco, California. Holders of common stock of record at the close of business on March 14, 2006 are entitled to notice of and to vote at the annual meeting.

      The following table summarizes, as of December 31, 2005, certain information regarding equity compensation to our employees, officers, directors and other persons under our equity compensation plans.

Equity Compensation Plan Information

      The table below provides a summary of all repurchases by Tesoro of its common stock during the three-month period ended December 31, 2005.

      The following table sets forth certain selected consolidated financial and operating data of Tesoro as of the end of and for each of the five years in the period ended December 31, 2005. The selected consolidated financial information presented below has been derived from our historical financial statements. Our financial results include the post-acquisition results of our California operations since mid-May 2002 and our Mid-Continent operations since September 2001. The following table should be read in conjunction with Management’s Discussion and Analysis of Financial Condition and Results of Operations in Item 7 and our consolidated financial statements in Item 8.

      Those statements in this section that are not historical in nature should be deemed forward-looking statements that are inherently uncertain. See “Forward-Looking Statements” on page 46 and “Risk Factors” on page 16 for a discussion of the factors that could cause actual results to differ materially from those projected in these statements.

BUSINESS STRATEGY AND OVERVIEW

      Our strategy is to create a value-added refining and marketing business that has (i) economies of scale, (ii) a low-cost structure, (iii) effective management information systems and (iv) outstanding employees focused on business excellence in a global market, that can provide stockholders with competitive returns in any economic environment.

      Our goals are focused on: (i) operating our facilities in a safe, reliable, and environmentally responsible way; (ii) improving profitability by achieving greater operational and administrative efficiencies; and (iii) using excess cash flows from operations in a balanced way to create further shareholder value.

      In November 2005, our Board of Directors approved the 2006 capital budget, which is currently estimated to be $670 million (including refinery turnaround and other maintenance costs of approximately $105 million). The 2006 capital budget includes the modification of our existing fluid coker unit to a delayed coker unit at our California refinery which is designed to (i) lower emissions as required by the Bay Area Air Quality Management District (see “Environmental and Other”) and (ii) increase overall efficiency by lowering operating costs. We currently expect to spend approximately $275 million through the fourth quarter of 2007 for this project, of which $3 million was spent in 2005. We anticipate spending $133 million in 2006, $138 million in 2007 and the remainder in 2008. This cost estimate is subject to further review and analysis.

      Our Board of Directors has approved certain high return and strategic capital projects, including installing a 25,000 bpd delayed coker unit at our Washington refinery and a 10,000 bpd diesel desulfurizer unit at our Alaska refinery. The delayed coker unit will allow our Washington refinery to process a larger proportion of lower-cost heavy crude oils and manufacture a larger percentage of higher-value products. We expect to spend approximately $250 million through the fourth quarter of 2007 for this project, of which we spent $2 million in 2005. We anticipate spending $110 million in 2006 and the remainder in 2007. The diesel desulfurizer unit, which will allow us to manufacture additional quantities of low sulfur diesel at our Alaska refinery, will require us to spend approximately $55 million through the 2007 second quarter, of which we spent $4 million in 2005. We anticipate spending $39 million in 2006 and the remainder in 2007. These cost estimates are subject to further review and analysis.

      In 2005, Tesoro’s incentive compensation program included two financial goals focused on improving profitability by achieving greater operational and administrative efficiencies: (i) achieve earnings of at least $3.85 per diluted share for executives and $3.50 per diluted share for all other eligible employees and (ii) realize $62 million of operating income improvements through business improvement initiatives that are principally generated by intellectual capital rather than capital investment. During 2005, we achieved the following significant results relative to our goals, which are further described below under “Results of Operations” and “Capital Resources & Liquidity”:

      Industry refining margins remained strong during 2005 and improved as compared to 2004. Factors positively impacting industry refining margins during 2005 included:

RESULTS OF OPERATIONS

      Our net earnings for 2005 were $507 million ($7.44 per basic share and $7.20 per diluted share), compared with net earnings of $328 million ($5.01 per basic share and $4.76 per diluted share) for 2004. The significant increase in net earnings during 2005 was primarily due to (i) higher refined product margins, (ii) record high throughput levels, and (iii) realizing our operating income improvement initiatives. Net earnings for 2005 included charges for debt refinancing and prepayment costs of $58 million after-tax or $0.82 per share, and executive termination and retirement costs of $6 million after-tax, or $0.09 per share. Net earnings for 2004 included debt prepayment and financing costs of $14 million after-tax, or $0.20 per share, and charges for executive retirement costs of $1 million after-tax, or $0.01 per share.

      Our net earnings for 2004 were $328 million ($5.01 per basic share and $4.76 per diluted share), compared with net earnings of $76 million ($1.18 per basic share and $1.17 per diluted share) for 2003. The significant increase in net earnings during 2004 was primarily due to (i) higher refined product margins, (ii) increased throughput levels, (iii) lower interest expense as a result of debt reduction and refinancing in 2003 and additional debt prepayments during 2004, and (iv) our continued focus on capturing business improvement initiatives. Net earnings for 2003 included the write-off of unamortized debt issuance costs of $23 million after-tax, or $0.35 per share. Our 2003 results also included losses on the sale of our marine services assets and certain retail asset impairments of $6 million after-tax, or $0.09 per share, voluntary early retirement benefits and severance costs of $6 million after-tax, or $0.09 per share, and a charge related to the termination of our funded executive security plan of $6 million after-tax, or $0.08 per share.

      A discussion and analysis of the factors contributing to our results of operations is presented below. The accompanying consolidated financial statements in Item 8, together with the following information, are intended to provide investors with a reasonable basis for assessing our historical operations, but should not serve as the only criteria for predicting our future performance.