While Burr sat on committees focused on health care, taxes and trade, he and his wife bought and sold hundreds of thousands of dollars of stock in an array of health care companies, banks and corporations with business overseas. At times, Burr owned stock in companies whose specific industries he advanced through legislation.

Those trades are entirely legal, as long as he can prove that he didn’t act on private information. But the co-mingling of legislative responsibilities and personal financial dealings has long worried ethics specialists, who insist that such trading amounts to a serious conflict of interest, even if it doesn’t reach the level of insider trading.

“Maybe the bottom line is, if you’re going to be in the Senate you can’t own any stock. Or at least own mutual funds. Who knows, people could say you’re gaming an index fund,” Sen. John Cornyn (R-Texas) told POLITICO this week.