Skip to content

Premcor

Premcor was a United States oil-refining company that operated a network of large petroleum refineries before being acquired by Valero in 2005.

Last updated August 26, 2026

AI crawler reads

No AI crawler has read this profile since Oct 28, 2026.

Overview

Premcor was a United States oil-refining group headquartered in Greenwich, Connecticut. The company operated as a major independent refining business and was listed on the New York Stock Exchange under the symbol PCO before its acquisition by Valero in 2005. Its business centered on processing crude oil into refined petroleum products through a geographically distributed portfolio of large refineries. By July 2007, Premcor's former operating network comprised five refineries located in Port Arthur, Texas; Memphis, Tennessee; Lima, Ohio; Hartford, Illinois; and Delaware City, Delaware. Together, these facilities had an approximate crude-oil processing capacity of 768,120 barrels per day, equivalent to about 122,121 cubic metres per day. The portfolio gave the company exposure to several important refining regions in the United States, including the Gulf Coast, the Midwest, and the Mid-Atlantic area. Premcor's corporate identity ended as an independent enterprise when Valero acquired the company in 2005. After the transaction, the facilities became part of Valero's broader refining network and were managed according to Valero's portfolio strategy. Subsequent changes to the assets illustrate that the former Premcor refinery group was not preserved as a single unchanged operating unit: Valero sold the Lima, Ohio, refinery to Husky Energy in July 2007, while the Delaware City refinery was closed in November 2009. The available reference material identifies Premcor primarily through its refining assets, public-market status, acquisition by Valero, and the later disposition or closure of individual facilities. It does not establish a separate consumer-facing product brand, a founder, an original founding date, or a current operating business. Premcor is therefore best understood as a defunct corporate refining group rather than an active retail fuel brand.

History

Premcor was a United States petroleum-refining group based in Greenwich, Connecticut. The available historical record presents the company principally as an operator of refinery assets rather than as a consumer brand. Before its acquisition, Premcor was publicly traded on the New York Stock Exchange under the symbol PCO and was described as a Fortune 500 oil-refining group. The company's operating model was built around a portfolio of large refineries distributed across several United States refining regions. By July 2007, the network associated with Premcor consisted of five facilities: Port Arthur, Texas; Memphis, Tennessee; Lima, Ohio; Hartford, Illinois; and Delaware City, Delaware. Their combined crude-oil processing capacity was approximately 768,120 barrels per day, or about 122,121 cubic metres per day. This geographic spread connected the group to Gulf Coast, Midwestern, and Mid-Atlantic refining markets. Premcor ceased to operate as an independent company after Valero acquired it in 2005. The acquisition transferred Premcor's refining assets into Valero's corporate system and ended the standalone public-market identity represented by the PCO ticker. The transaction was a major turning point because subsequent references to the refineries generally concern Valero's ownership and management rather than Premcor as a continuing company. The former Premcor portfolio later changed composition. In July 2007, Valero sold the Lima refinery in Ohio to Husky Energy. In November 2009, Valero closed the Delaware City refinery in Delaware. These events show that the assets inherited through the acquisition were subsequently evaluated and managed individually rather than maintained intact as a five-refinery Premcor network. The supplied reference material does not provide a confirmed founding year, founder, named executives, detailed product specifications, advertising campaigns, or a standalone website. It also does not document scandals or litigation associated with Premcor. Accordingly, the brand's documented historical significance rests on its role as a substantial American refining group, its former NYSE listing, its acquisition by Valero, and the later sale or closure of parts of its refinery portfolio.

  • 2009

    Delaware City refinery closed

    [1]

    Valero closed the former Premcor refinery in Delaware City, Delaware, in November 2009.

  • 2007

    Lima refinery sold to Husky Energy

    [1]

    Valero sold the former Premcor refinery in Lima, Ohio, to Husky Energy in July 2007.

  • 2005

    Acquired by Valero

    [1]

    Valero acquired Premcor, ending the company's independent corporate existence and absorbing its refinery assets.

Products and positioning

Independent United States petroleum refiner focused on operating large-scale crude-oil processing assets.

  • Petroleum refining

    Refined petroleum products

    Premcor's core business was the operation of crude-oil refineries. Its facilities converted crude oil into marketable refined petroleum products, including transportation fuels and other refinery outputs. The available reference material identifies the company by its refining capacity and facilities but does not provide a complete product-by-product slate.

Brand decisions

  • 2009

    Closure of the Delaware City refineryStrategy

    Background

    The Delaware City, Delaware, refinery was among the facilities associated with Premcor's former five-refinery network.

    Action taken

    Valero closed the Delaware City refinery in November 2009.

    Aftermath

    The closure further reduced and changed the refinery portfolio that Valero had acquired through Premcor.

  • 2007

    Sale of the Lima refineryM&A

    Background

    The Lima, Ohio, refinery was part of the refinery network inherited by Valero from Premcor.

    Action taken

    Valero sold the Lima facility to Husky Energy in July 2007.

    Aftermath

    The Lima refinery left the former Premcor-derived asset portfolio and became part of Husky Energy's operations.

  • 2005

    Valero's acquisition of PremcorM&A

    Background

    Premcor was a publicly traded United States refining group with a substantial multi-refinery operating portfolio.

    Action taken

    Valero acquired Premcor and integrated its refinery assets into Valero's operations.

    Aftermath

    Premcor no longer operated as an independent company. Its former refineries subsequently became subject to Valero's asset sales and operating decisions.

Sources1 sources

Cite this profile: Cite the canonical profile. /brand-wiki/premcor · Editorial policy · How profiles are compiled