President-elect Donald Trump’s choice to be Health and Human Services secretary sold shares of once high-flying biotech company Gilead Sciences Inc. in March while buying those of marquee drugmakers including Pfizer Inc. and Eli Lilly & Co. They are among the latest trades reported by Rep. Tom Price, a Georgia Republican who’s long been an investor in medical stocks, according to congressional filings.

Members of Congress can buy and sell shares, even if the committees on which they serve directly influence federal policies affecting companies whose stock they own. Still, they should avoid actively investing in industries they oversee, said Richard W. Painter, who was an ethics lawyer for President George W. Bush’s administration. While there’s little chance that a lawmaker will have knowledge affecting a company’s stock price beyond what’s known to the general public, it raises questions, Painter said.

Price is a member of the Ways and Means subcommittee on health, which oversees Medicare. Even if Price doesn’t have any insider knowledge affecting his purchases due to his position in Congress, Painter said, his trading in health care shares creates the appearance of a conflict of interest.

“Good judgment would be to stay out of health care stocks if you are on a health-care related committee,” Painter, who is now with the University of Minnesota Law School, told CQ Roll Call. “Stay out of energy stocks if you are on an energy committee. Stay out of defense stocks if you are on Armed Services.”

A spokesman for the transition team for HHS defended Price. If confirmed as secretary of HHS, “Dr. Price intends to comply fully with all applicable laws and ethics rules governing his personal finances — just as he does currently as a member of Congress,” said spokesman Phil Blando in a statement to CQ Roll Call.