The 11 percent plummet by the S&P 500 index between Aug. 17 and Aug. 25 put a major hurt on hedge funds that were bullish stocks.

Among the losers from the global stock plunge are star managers Leon Cooperman, Raymond Dalio and Daniel Loeb. Cooperman’s Omega Advisors suffered a 12 percent slide for August through Wednesday, according to The Wall Street Journal.

Loeb’s Third Point and William Ackman’s Pershing Square Capital Management also have endured significant losses, putting them in the red for 2015.

“We’ve struck out this month so far,” one hedge-fund manager told the paper.

Journal reporter Rob Copeland notes the irony that as hedge fund managers have underperformed the stock market during its 6 ½-year rally, they offered the excuse that they were hedging the move, just as hedge funds were meant to do. It looks like many didn't hedge it too skillfully.

To be sure, not all fund managers screwed up. Stock hedge funds are down an average of 5 percent this month, besting the 7.8 percent decline for the S&P 500, according to HFR.

Elsewhere on the equity front, the market's plunge is bad news for individual investors and could help drive them away from stocks for years, says ace hedge fund manager Doug Kass, president of Seabreeze Partners Management.

He lists several factors that could repel investors from equities in a commentary on TheStreet.com.

• "The Ongoing Bear Market." The stock drop was preceded by a plunge in commodity prices that has sent major indices to 16-year lows. Gold fell to five-year lows, and oil prices have hit six-year lows. "Big Oil and others hit by this bear market are often mainstays in retail investors' accounts," Kass writes.
• "A Broken Market Mechanism. The market's mechanism has been virtually destroyed by increased and more-costly regulatory burdens," Kass says. "These serve to limit dealer inventories in numerous asset classes and impair market liquidity, creating a vacuum that's taken up by leveraged ETFs and high-frequency trading strategies."

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