How bad has the start to December been for U.S. stock investors? Almost $1 trillion has been wiped from the value of stocks in just four days of trading.

The Russell 3000 has plunged 4.9 percent this week as of 3 p.m. Friday in New York, as the six-week rout in American stocks deepened amid concern global growth is slowing and the Trump administration will escalate trade tensions.

Apple’s 5.4 percent plunge lowered its value by $45 billion, while Amazon’s 3 percent slide left it worth $24 billion less than a week ago.