Shares of Amazon, Apple, Facebook, Netflix and Google fell Thursday morning, as tech investors evidently have grown more concerned that President-elect Donald Trump will adopt unfavorable policies toward Silicon Valley.

In mid-morning trading, shares of Netflix, Facebook and Amazon fell more than 4%. Apple’s stock was down 2.9%, while Google declined 3.4%. That was below broader market indices, with the S&P 500 down 0.2% and the Nasdaq off 1.16%.

As a candidate, Trump had called for a boycott of Apple products over its refusal to cooperate with federal agents investigating the terrorist attack in San Bernardino, Calif., last year, and he’s urged the company to bring its manufacturing operations to the U.S.

Trump also has charged that Amazon is a monopoly that has avoided paying billions in taxes — and has accused CEO Jeff Bezos of buying the Washington Post, which has been a frequent critic of Trump, as a tax dodge. Meanwhile, the mogul/reality TV star has said he opposes the FCC’s network neutrality regulations. That’s fueled speculation he will try to repeal the rules, which would be a setback for companies like Google, Netflix, Facebook and Amazon.

In addition, Trump’s protectionist positions on international trade and calls for greater restrictions on immigration also run counter to tech companies’ interests.

Bezos posted a congratulatory tweet to Trump on Thursday, apparently seeking to build a bridge to the new administration after Trump’s harsh criticism of his company:

Apple CEO Tim Cook, meanwhile, sent a memo Wednesday to U.S. staffers urging them to stay calm and focused in the wake of Trump’s election.

“While there is discussion today about uncertainties ahead, you can be confident that Apple’s North Star hasn’t changed,” Cook said in the memo, which was obtained by BuzzFeed. “Our company is open to all, and we celebrate the diversity of our team here in the United States and around the world — regardless of what they look like, where they come from, how they worship or who they love.”

Facebook chief Mark Zuckerberg, in a post on Wednesday evening on the social site, didn’t address how a Trump presidency might affect his company. Instead, he wrote optimistically about the future for his 11-month-old daughter, Max.

“Holding Max, I thought about all the work ahead of us to create the world we want for our children,” Zuckerberg wrote in the post, which he tagged with “feeling hopeful.” “This work is bigger than any presidency and progress does not move in a straight line. The most important opportunities of Max’s generation — like curing all disease, improving education, connecting everyone and promoting equal opportunity — will take long term focus and finding new ways for all of us to work together, sometimes over decades.”