Want to get legislation you favor passed at the federal level? Talk to your U.S. representative or senator. Want to get some good stock ideas? You might want to talk to your representative or senator on this one, too.

Many members of Congress actively invest in the stock market. They often (although not always) achieve exceptional returns.

You probably won't be surprised that the energy sector was a favorite for several representatives and senators. Meet the surprising oil stock lawmakers couldn't stop buying in 2023.

The most bought stock of the U.S. Congress last year

I suspect most of us would guess members of Congress invested the most in ExxonMobil or Chevron last year. After all, they're the two biggest U.S. oil and gas producers by market cap.

However, neither of these oil giants ranked at the top of the list. Instead, the distinction belonged to ConocoPhillips (COP -0.56%). Lawmakers shelled out $2.5 million to buy ConocoPhillips shares in 2023. ConocoPhillips wasn't just the most bought oil stock for Congress; it edged out Apple for the top spot among all stocks purchased by U.S. representatives and senators.

One interesting thing stands out about congressional investing in ConocoPhillips last year. House Republicans did the vast majority of the buying. Democrats and senators of either party didn't invest nearly as heavily in the oil stock.

Rep. Michael McCaul, R-Tex., was the most active buyer of ConocoPhillips on Capitol Hill in 2023. All of his purchases, however, were for his spouse or children.

Why ConocoPhillips?

It makes sense why McCaul would invest in ConocoPhillips. The company's headquarters is in Houston, Texas. McCaul represents the 10th District in Texas, which extends from Austin to Houston.

But why would other members of Congress, including Democrats Ro Khanna of California and Lois Frankel of Florida, buy the oil stock? Both Khanna and Frankel invest in a wide range of stocks and sectors. Khanna ranked as the most active trader in Congress last year, while Frankel took the No. 6 spot.

Lawmakers could have been attracted to ConocoPhillips' valuation. The stock traded at a price-to-earnings ratio of below 10 throughout the first half of 2023.

ConocoPhillips' dividend was also a potential factor behind the buying. The company's dividend yield was above 3.2% for most of last year and topped 4% a few times.

Is this oil stock a buy now?

Congressional investments in ConocoPhillips didn't pay off much in 2023. The stock slipped nearly 2% lower while the S&P 500 soared 24%. However, ConocoPhillips' shares are up more than 10% year to date. I think the stock will move higher.

The turmoil in the Middle East has caused oil prices to rise. Some industry analysts predict crude oil could hit $100 per barrel this year (from around $82 now). If that happens, ConocoPhillips stock should have significantly more room to run.

Occidental Petroleum CEO Vicki Hollub expects an oil supply shortage by late 2025. If she's right, ConocoPhillips would almost certainly jump.

So far in 2024, no members of Congress have disclosed purchases of ConocoPhillips stock. In my view, now is a great time for them -- and other investors -- to invest in oil stocks. Although ConocoPhillips isn't my favorite pick, I think it's still a pretty good one.