Advertising Leaders Predict a ‘Period of Uncertainty’ Following Trump’s Surprise Win

International stock prices took a deep dive immediately before and after the Associated Press called the race for Trump last night but generally recovered thanks to a boost in biotech and defense companies; healthcare stocks remain volatile.

Advertising executives were watching the news closely. Stock prices for Publicis Groupe, WPP and Omnicom all dropped sharply last night, though each has largely recovered.

The leaders of these companies urged caution following Trump's win. In statements emailed to Business Insider, The Drum and other news outlets, WPP chief executive Sir Martin Sorrell called the election "effectively a second Brexit," stating that the news "leaves many surprised, including the markets and me."

"It's going to take a significant time to assess the implications beyond the short-term," Sorrell added. "Increased levels of uncertainty will mean more hesitation to make important decisions in the short-term, both by people and governments. But it may accelerate implementation of helpful reforms in the medium-term to reduce uncertainty and stimulate investment as a result."

"The election supports the idea that the American people want change, and with that change will come a period of uncertainty. Time will tell what the impact will be on the economy," said Omnicom CEO John Wren in a statement. "Clearly the middle class has spoken, both in the U.S. and Western Europe, and challenges like immigration, terrorism and trade where key issues that impacted the electorate."

Wren continued, "Now that Mr. Trump is president-elect we will have to wait and see how he will govern and who he selects as his cabinet members and advisors. While it is too early to tell what this change will mean for our industry and advertising and media spending, the American people, corporations and its institutions are resilient and we expect they will adapt to the new political landscape."

Interpublic Group CEO Michael Roth told The Wall Street Journal today that he feared the news might have a "chilling effect" on ad spend totals in the short term, and Publicis Groupe chairman and CEO Maurice Levy said he was "cautious about the clouds on the horizons" related to the election in his company's quarterly earnings report last month.

Publicis representatives did not respond to requests for comment on Trump's win today.

These executives' statements were similar to those made following this summer's Brexit vote. "We must deploy that stiff upper lip and make the best of it," Sorrell said in June, while Roth stated that "The decision will lead to market volatility in the short term, no question" but theorized that markets would eventually normalize following the initial shock.