Ask Matt: What firms would go if Texas secedes?

• Talk about states seceding, especially Texas, has popped up since the election
• Texas is home to 51 stocks in the Standard and Poor's 500 index
• The region is reliant on large energy companies but also has a tech footprint

USA TODAY markets reporter Matt Krantz answers a different reader question every weekday. To submit a question, e-mail Matt at mkrantz@usatoday.com.

Q: What public companies would no longer be based in the U.S. if Texas seceded?

A: Voters who don't get their way after a U.S. presidential election are understandably upset. Some, though, aim to do something about it.

After many charged elections, the topic of secession often comes up. Disappointed voters in states who wanted another candidate to win often talk about leaving the U.S. so they can go in a different political direction.

Cable talk-show chatter, as well as some online petitions, have created the idea that some states might think about leaving the U.S. Texas is often one of the leading states with the secession mind-set.

It's important to note the idea of secession is far from being even remotely considered realistic. Nonetheless, some investors might be curious to know what some of the largest companies in this political hotbed are.

Limiting the search to publicly traded companies in the Standard & Poor's 500 gives a very revealing look at what firms and industries are the key to Texas. Currently, 51 stocks in the S&P 500 hail from the Lone Star State. By far, the oil and gas industry is Texas' major contribution to the halls of the nation's biggest companies.

The largest company in Texas, based on total revenue, is integrated energy company ExxonMobil. ExxonMobil is followed by ConocoPhillips, Phillips 66 and Valero Energy as No. 2, No. 3 and No. 4 biggest companies in the state.

After the energy giants, the big companies drop off fast in size. Next, at No. 5 is AT&T, followed by technology firms Dell and Schlumberger.

While Texas is home to many key companies, it still trails California and New York as the home for large companies. California has 65 S&P 500 companies and New York has 55.