Robotic selling by quantitative investment funds tuned to volatility and price trends contributed to last month’s losses in U.S. stocks and is only about halfway completed, according to a JPMorgan Chase & Co. strategist.

Traders employing trend-following strategies in futures and those who use an asset-balancing technique known as risk parity probably have to get rid of another $100 billion in stocks in the next one to three weeks, wrote Marko Kolanovic in a note Thursday to clients. While down from an estimate of $300 million in research published a week ago, the derivatives strategist said investors shouldn’t consider the risk as having passed.

“We expect elevated volatility and downside price risk to persist,” Kolanovic wrote. “In our view, the risk/reward for equity investors remains in favor of waiting, rather than being fully invested until there is more clarity from macro data and central banks.”

Computerized traders whose behavior is triggered by market signals like volatility or price trends rather than earnings or the economy have gotten extra attention since stocks began their biggest swoon in four years last month. Kolanovic predicted on Aug. 21 that quantitative funds had the potential to exacerbate swings in equities after the S&P 500 broke below a trading band that had held for most of the year.