Following the 1911 Supreme Court ruling that found Standard Oil was an illegal monopoly, the company was broken up into 43 different entities, divided primarily by region and activity. Many of these companies later became part of the Seven Sisters, which dominated global petroleum production in the 20th century, and became a majority of today's largest investor-owned oil companies, with most tracing their roots back to Standard Oil. Some descendants of Standard Oil were also given exclusive rights to the Standard Oil name.
Today, many of Standard Oil's 43 successor entities play roles in the oil industry, either on their own or through being acquired by other companies. Standard Oil of New Jersey, the controlling division of Standard Oil at the time of the 1911 breakup, continues to exist as ExxonMobil, formed from the merger of it and Standard Oil of New York. BP has also acquired many Standard Oil descendants, most notably Standard Oil of Ohio and Amoco (Standard Oil of Indiana). Saudi Aramco, the state-owned oil company of Saudi Arabia, also traces its origins to Standard Oil as the Arab kingdom founded it in a partnership with Standard Oil of California, today known as Chevron Corporation. Other companies themselves not primarily focused on the petroleum industry have owned or previously owned Standard Oil descendants, including U.S. Steel (which previously owned Marathon Oil), the first incarnation of DuPont (which previously owned Conoco), and Unilever (which presently owns Chesebrough and Vaseline). Among Standard Oil's largest non-petroleum descendants is the credit bureau TransUnion, which originally was divested from the Standard-descending Union Tank Car Company.
Background
In the 1911 breakup, the Supreme Court found that Standard Oil conspired to restrain the trade and commerce in petroleum, and monopolized the commerce in petroleum, in violation of the Sherman Antitrust Act.
Major direct descendants
Standard Oil's largest direct descendants which today are still their own independent companies are ExxonMobil, a merger of the Standard Oil Companies of New Jersey and New York, and Chevron, a rebranding of the Standard Oil Company of California since its own acquisition of Gulf Oil.
ExxonMobil (Standard Oil of New Jersey and New York, and Vacuum Oil)
ExxonMobil is mostly composed of the Standard Oil Company of New Jersey (Jersey Standard) and the Standard Oil Company of New York (Socony). The two companies partnered on a semi-frequent basis during their infancy before pursuing mergers and acquisitions, with Jersey Standard buying Texas-based Humble Oil and Socony merging with Standard descendant Vacuum Oil to form Socony-Vacuum. The two companies collaborated in certain cases, such as a joint ownership of Standard Vacuum Oil Company.
In retail, Jersey Standard used three brand names to market its products to American motorists: Esso, Enco, and Humble (after its acquisition). Jersey Standard preferred to sell as Esso in all states, though due to the formation of Esso being from a phonetic transliteration of the initials of Standard Oil (S.O.), courts prevented Jersey Standard from selling as Esso everywhere. To solve this, Jersey Standard announced it would rebrand all of its stations as Exxon in 1973, and changed its corporate name to that of Exxon Corporation simultaneously. Meanwhile, Socony-Vacuum gradually began to use Mobiloil and Mobilgas as trade names for its retail products, and the company eventually changed its name to Mobil Corporation in 1955.
In the late 1990s, the two companies began merger talks and the deal was closed with American regulatory approval (albeit with a nearly 2,500 retail station divesture) in November 1999. ExxonMobil today is the largest majority investor-owned oil and gas corporation in the world by market capitalization and revenue, ranking twelfth on the Fortune Global 500 in 2022, and 11th by market capitalization as of September 29, 2022.
Chevron (Standard Oil of California and Kentucky)
Originally an independent oil company known as the Pacific Coast Oil Company, Standard Oil acquired Pacific Coast in 1900, renaming it the Standard Oil Company of California and granting it the assets of Standard Oil of Iowa, assets that were retained by the CalSo breakup of the larger Standard Oil. From the 1930s onward, CalSo invested primarily in its namesake state as well as in the Arabian Peninsula, with its operations there eventually being fully bought out by Saudi Arabia's government in 1980 and merged into what is today known as Saudi Aramco. In 1961, CalSo acquired Standard Oil of Kentucky.