"For hedge funds, shorts have been a challenge since early June especially," JPMorgan said, adding the unwinding of short positions got "extreme" in recent days.
The outcome for hedge funds has not been good.
Overall, hedge funds went up 3.45% in the first half of the year, lagging the main stock indexes.
Net buying, which excludes stocks sold, reached its largest level since October last year, according to Goldman Sachs.
Still, hedge funds also shorted more single stocks, mainly in sectors like staples, communication services and info tech, according to Goldman Sachs.
Persons:
JPMorgan Chase, Goldman Sachs, Carolina Mandl, Nell Mackenzie, Nick Zieminski
Organizations:
Global, JPMorgan, Nasdaq, Thomson
Locations:
U.S, New York, London