All major indexes began the day in negative territory, but turned positive 20 minutes after trading began. That rally was short lived, however. As of 11:15 a.m. ET, the Dow Jones Industrial Average was down 243 points (0.61%), the S&P 500 sank 30 points (0.58%) and the Nasdaq index dipped 77 points (0.47%). A little after noon, averaged were once again moving higher.

The Dow has seen a swing of nearly 500 points in the first half of the trading day.

Stocks started the week higher than they began it, thanks to Wednesday’s market rally. Since the so-called Liberation Day announcements, though, the Dow has lost 6% of its value, with Nasdaq and S&P both down 7%.

This week has been one of the most volatile in Wall Street’s history as uncertainty over trade policies took its toll on a wide swath of companies. Earlier this week, the CBOE Volatility Index spiked above 50. As of the market open, it was close to 45.

The drop on Wall Street follows China’s announcement that it was retaliating against U.S. tariffs, raising its own levies on U.S.-made products to 125% from the previous level of 84%. Chinese officials signaled this was as high as they planned to go, even if the U.S. raises its tariffs against Chinese goods further.

There was some hope for the trade wars to calm some as the trade representative for the European Union plans to fly to Washington on Sunday to “try and sign deals.”