The rout in U.S. stocks last week spurred the heaviest withdrawals since the 2000 dot-com crash for the biggest exchange-traded fund tracking U.S. technology shares.

Investors yanked almost $4 billion from the $56 billion PowerShares QQQ Trust Series 1 ETF in the five days ended Feb. 9, outpacing redemptions at the depths of the financial crisis. The SPDR S&P 500 ETF Trust, the world’s biggest fund, saw a record $23.6 billion of outflows.

Trading volume for the tech ETF, which tracks the Nasdaq 100 Index, jumped to more than 500 million shares over the five tumultuous trading sessions, the most since August 2011.

This article was provided by Bloomberg News.