Pharmaceutical stocks surged in Europe on Wednesday as Republican Donald Trump’s U.S. presidential election win led investors to conclude the threat of tough action on drug pricing had receded.

News that a California ballot initiative aimed at reining in rising prices for prescription drugs was headed for defeat also buoyed the mood, with shares in major European drugmakers rising between 2 and 6 percent

Trump’s victory over Hillary Clinton, whose drug pricing criticisms have weighed on shares for more than a year, is not without risk, however. A Republican pledge to repeal Obamacare could have potentially chaotic consequences.

Zuercher Kantonalbank analyst Michael Nawrath said uncertainty over how Trump will make good on his promise to scrap the Affordable Care Act, widely known as Obamacare, could weigh in the months ahead.

“He’ll clearly have advisers helping him. We’re going to have to see which proposals emerge,” he said.

Healthcare was the biggest sector gainer in Europe following Trump’s win, with the Stoxx 600 healthcare index up 3.5 percent by 1130 GMT.

Danish insulin maker Novo Nordisk nvo , whose diabetes drug prices have been under fire recently in the United States, saw some of the largest gains, rising 6 percent.

A spokesman for Novo, which generates more than half of its sales in the United States, said the company was pleased by the Californian ballot news, but added that it was “unpredictable” what the Trump presidency meant for the drugs industry.

Shares in other major drugmakers like Roche, Novartis nvs , Sanofi, AstraZeneca azn and GlaxoSmithKline gsk rose between 2 and 4.5 percent.

U.S. drug maker Mylan myl , which has come under fire in recent months for hiking the price of its two-pack EpiPen allergy shot to more than $600, leapt 8 percent in Tel Aviv . In pre-market trading in the U.S., meanwhile, Eli Lilly lly was tipped to open up 3.1%, Merck & Co mrk up 3.1% and Pfizer Inc. pre up a whopping 8%.

Throughout the campaign Clinton had been far more critical of drug industry pricing than Trump, famously sending drug stocks into a tailspin in September 2015 when she tweeted about specialty drug “price gouging.”

Trump has said less on the topic but he has suggested support for importation of cheaper drugs, as well as advocating increased scrutiny over drug price increases and a bigger role for negotiating down the cost of medicines.

Marie Owens-Thomsen, chief economist at Indosuez Wealth Management, believes the idea that he is the good news candidate for the pharmaceuticals industry is “a bit of a simplistic view.”

“He has made several statements that are also potentially harmful,” she said.

Jefferies analysts said U.S. pricing pressure and political reform would remain a concern but Trump’s win would be a relief for investors worried about a sea change in the U.S. system, where innovation is rewarded by high prices.

Switzerland’s Roche, the world’s biggest maker of cancer drugs, echoed the belief that the United States would remain a rewarding market.

“Roche is focused on developing innovative medications and diagnostic tests and we are convinced that the U.S. will continue to value and support innovation and medical progress,” said a company spokesman.