Fortune magazine has announced its ranking of the world's 500 largest companies, and two San Antonio companies made the list.

San Antonio's Valero Energy Corp. was No. 26 in the U.S. and No. 84 in the world with $70 billion in revenue, according to Fortune's Global 500 list. USAA, also based in San Antonio, ranked 135 nationally and 483 in the world with $17 billion in revenue.

At the top of the list was Wal-Mart Stores, which posted the most revenues of any country in the world with $408 billion.

Irving-based Exxon Mobil Corp. topped the Texas companies that made the list. It was the second-ranked U.S company and third-ranked worldwide with revenues of $284 billion.

AT&T, which relocated to Dallas from San Antonio in 2008, was No. 7 in the country and No. 21 in the world with $123 billion in revenue.

In Houston, six companies made the list. ConocoPhillips topped that city's list at No. 6 in the country and No. 17 in the world with $139 billion in revenue. Marathon Oil Corp. ranked 43 in the country and 144 in the world with $49 billion in revenue, Sysco Corp. was No. 57 in the country and 194 in the world with $36 billion in revenue, Enterprise GP Holdings ranked 94 in the country and 325 in the world with $25 billion in revenue, oilfield services provider Schlumberger ranked 111 in the country and 380 in the world with $22 billion in revenue and Plains All American Pipeline ranked 131 in the country and 464 in the world with $18 billion in revenue.