Hedge funds have been hit with the biggest margin calls since Covid shut down huge parts of the global economy in 2020, after Donald Trump’s tariffs triggered a powerful rout in global financial markets.

Wall Street banks have asked their hedge fund clients to stump up more money as security for their loans because the value of their holdings had tumbled, according to three people familiar with the matter. Several big banks have issued the largest margin calls to their clients since the beginning of the pandemic in early 2020.

The margin calls underscore the intense turbulence in global markets on Thursday and Friday as Trump’s tariffs announcement was followed by retaliatory duties by China, and other countries readied their own responses. Wall Street’s S&P 500 share index was set to post its worst week since 2020, while oil and riskier corporate bonds have sold off heavily.