Citadel, JAT Capital

Och-Ziff's main OZ Master Fund lifted its return to 1.2 percent this year, said an investor who asked not to be identified because the information isn't public.

Citadel LLC's two largest funds were little changed and gained 14 percent this year through last week, said a person with knowledge of the results, who asked not to be named because the information is private. Citadel, which is based in Chicago and oversees about $11 billion, is run by Ken Griffin.

JAT Capital Management, the New York-based fund run by John Thaler with about $2 billion, was little changed after posting a 32 percent gain this year through July, according to a client who asked not to be named because the returns aren't public.

Stocks Retreat
London-based Marshall Wace LLP's $400 million MW Global Opportunities Fund, which is managed by Fehim Can Sever, has risen 5 percent this month, according to a person familiar with the matter who asked not to be named because the information is private. The fund, which invests in stocks, has gained 10 percent this year, said the person.

Investors continued to flee riskier assets on Aug. 8, the first trading session after Standard & Poor's cut U.S. debt to the second-highest level of AA+ from AAA.

Federal Reserve policy makers met yesterday after the unprecedented downgrade of the government's top credit rating shook confidence in the U.S. economic recovery.

The S&P 500 surged to close with a gain of 4.7 percent after the Fed pledged for the first time to keep its benchmark interest rate at a record low at least through mid-2013 to revive a recovery that's "considerably slower" than anticipated. Today, the index retreated, losing 3.6 percent at 10:13 a.m. New York time.

Among funds that suffered losses last week is John Paulson's Advantage Plus Fund, which fell 11 percent and is now down 31 percent since the start of the year, according to a person familiar with the firm. New York-based Paulson & Co. manages $15.7 billion in various Paulson Advantage funds.

Lansdowne, SAC Losses
Lansdowne Partners Ltd., the $14 billion hedge fund in London, was hurt last week by its holdings in financial firms including Lloyds Banking Group Plc and Wells Fargo & Co.