Net Net: Promoting innovation and managing change
Net Net: Promoting innovation and managing change

George Soros loads up on bearish market bet

George Soros bearish on S&P 500

Soros Fund Management, the large family office that manages assets for billionaire George Soros, raised its protection against a U.S. stock market drop dramatically, sparking concerns that the powerful investment firm is expecting a big fall in equities.

During the course of the second quarter, which ended June 30, Soros Fund Management's position in puts—the right to sell at a certain price at an appointed time in the future—in a popular exchange-traded fund tracking the rose to 11.29 million shares, which appears to be a multiyear high for the investment manager. (During the first quarter, the size of that position was just 1.6 million puts, meaning that the second quarter marked a 606 percent increase.)

Based on some simple math, and assuming Soros still held the puts and that they were in the money (meaning they would generate gains if they were exercised today), the notional value of the bearish position is roughly $2.2 billion.

George Soros, billionaire and founder of Soros Fund Management, speaks during an interview in London in March.
Simon Dawson | Bloomberg | Getty Images

Read More

Soros Fund Management also held calls—the rights to buy S&P ETF shares at an appointed time in the future—as well as outright shares of the ETF, but in much smaller amounts.

A Soros spokesman could not immediately be reached for comment on the fund's market outlook. But competing money managers said not to put too much weight into what is apparently a pessimistic view of U.S. stocks, given that Soros Fund Management may simply be looking for a hedge to counterbalance its many long stock positions.

Read MoreHedge funds bet on Argentine recovery

"Hedge fund stocks have really gotten destroyed in the last three weeks," said one long-short stock manager Friday morning. "We're in a difficult time here."

—By CNBC's Kate Kelly