Health insurance stocks jumped after Donald Trump won the presidential election on expectations for deregulation in the industry, but shares tumbled after the killing of UnitedHealthcare CEO Brian Thompson.

In UnitedHealth’s case, the stock surged as much as 9% in the immediate aftermath of the election, but has sold off 15% since Dec. 4.

Even with Republicans poised for unified control of Congress and the White House, the pre-election narrative on insurers now looks shakier, John Ransom, director of healthcare research at Raymond James, told CNBC on Tuesday.

“I think the bet is a little bit hard to make because you don’t know who’s going to be occupying these seats,” he said. “And also, you do have a more populist party, and the industry is not as popular as it used to be.”

In fact, Thompson’s shooting unleashed a wave of online vitriol aimed at insurers over coverage that was denied to patients. Meanwhile, security firms have been flooded with calls from companies looking to ramp up protection for executives.

UnitedHealth Group CEO Andrew Witty addressed the criticism of his company in a New York Times op-ed on Friday and acknowledged the healthcare system needs improvement.

But the industry still faces a “legislative risk,” Ransom said, amid a debate on the use of artificial intelligence in so-called prior authorizations, which is when a service or prescription requires pre-approval from companies.

“That’s where I think there should be a healthy debate because maybe that has gotten out of control,” he added.

AI can still make a positive impact on healthcare, Ransom said. For example, large language models could be used to analyze difference datasets to help predict who might need services and intervene before a situation turns into a health crisis.

“But yeah, did we overdo it on prior auth?” he asked. “That’s the debate. I’m not saying we did, but I think that’s where we need to have a debate.”