The average hedge fund manager is losing money this year, but at least two of them - both proteges of legendary investor Julian Robertson - are posting gains of more than 20 percent.

Lee Ainslie's $9 billion hedge fund Maverick Capital lost 1.2 percent last month in the midst of a market rout, but its returns for the year are 20.5 percent, an investor source said on Thursday.

Nehal Chopra's $2 billion hedge fund Tiger Ratan, meanwhile, lost 6.6 percent last month, but remains up 21.6 percent year to date, an investor said.

Maverick and Tiger Ratan both specialize in stock picking and are among a handful of managers backed by billionaire investor Julian Robertson, whose Tiger Management once ranked among the world's biggest and most successful.

Ainslie, who has been in business for two decades, used to work for Robertson, and Chopra launched her firm 6 years ago with seed money from Robertson.

Robertson has backed other firms including Tiger Global and Viking Global Investors, whose founders once worked for him.

The average hedge fund lost about 2.2 percent last month and is down 1.5 percent for the year, data from Hedge Fund Research show. The Standard & Poor's 500, by comparison, lost 6 percent in August, driven by fears of slower growth in China, leaving it off roughly 5 percent for the year to date.

Some big name hedge funds, including William Ackman's Pershing Square, have reported sizeable losses for August that have put them into the red for the year.

A few other smaller firms, however, are among those retaining year-to-date double-digit gains, their investors said.

Jason Karp's Tourbillion Capital Partners lost 1.5 percent last month but is still up 18.4 percent for the year. Brahman Capital was off 1.9 percent last month, but is up 18.10 percent for the year, the investors said.