Global economists and executives from Apple Inc.’s Tim Cook to BlackRock Inc.’s Larry Fink gathered in Beijing this weekend against the backdrop a brewing trade war, after U.S. President Donald Trump slapped tariffs on Chinese goods affecting more than $50 billion worth of products.

The stakes are high for the U.S. economy and its multinational companies, Chinese officials and state media warned. Here is what some top economists and business leaders said at Saturday’s summit about rising trade tensions between the world’s two largest economies:

  • Tim Cook, Chief Executive Officer of Apple, said that he held passionate views on the issue and that he’d personally weighed into the debate. “The countries that embrace openness do exceptional and the countries that don’t, don’t,” he said. “It’s not a matter of carving things up between sides. I’m going to encourage that calm heads prevail.”
  • Larry Fink, Chairman and Chief Executive Officer of BlackRock, said that he believed dialogue and adjustments in trade policy can be in order. “The world needs a strong China and a strong U.S. The world does not need a public fight in which we reduce future opportunities,” he said.
  • Larry Summers, former U.S. Treasury Secretary, compared trade wars to nuclear war, which can never be won. He also said the biggest effect by far is a psychological impact on confidence. “This is also reflecting as much as it is leading a broad change in attitudes in the United States towards China.”
  • Sergio Ermotti, Chief Executive Officer of UBS Group AG, said he has begun to be concerned about a trade war but so far the numbers are modest in respect to the impact. “We see the proliferation of the tensions on a bilateral basis potentially escalating. This won’t be good for growth, won’t be good for geopolitical reasons,” he said.
  • Soren Skou, Chief Executive Officer of A.P. Moller-Maersk A/S, said a trade war will impact shipping negatively. “The case for free trade is very, very strong in terms of economic growth, in terms of job creation, in terms of benefits for producers and consumers.”
  • Li Daokui, a former adviser to the People’s Bank of China, said in an interview that President Donald Trump is challenging not just China but also the global trade system.