In a brutal year for high-profile hedge fund managers like Bill Ackman and David Einhorn, less-famous stock pickers focused on China stood out for their stellar performance.

China-focused managers betting on rising and falling stocks returned 11 percent in 2015, outpacing both the Shanghai Composite Index and the gauge of Hong Kong-listed stocks by a wide margin, while US funds narrowly beat benchmarks and European ones trailed, according to Eurekahedge Pte.

Stars included Hao Capital Management, with offices in Hong Kong and Shanghai, whose $268 million hedge fund surged 135 percent through November.

To justify their fees, hedge fund managers have to deliver alpha - outperformance relative to benchmarks - even in a market that's slammed several high-profile funds. Unlike peers in the United States and Europe, hedge funds investing in China have been able to exploit a market that has a wider dispersion between the best- and worst-performing stocks.

And despite lurching from one extreme to another, nine out of 10 stocks in the Shanghai Composite rose in 2015, helping managers sidestep big losses. This year will provide another test of managers' ability to handle volatility, with at least two China-focused funds posting large declines during a tumultuous start to 2016.

"China's stock market is much less efficiently priced," said Grace Lu, who manages the GH China Century Fund in Singapore. "If you are a good stock picker, it gives you more opportunities on the stock picking side compared to Europe and North America," said Lu, whose fund advanced 18 percent last year.

Large differences between the top and bottom returns of individual shares in China mean that good stock-picking can have an outsize impact. The median return of the top decile of the 1,112 companies traded in Shanghai was 150 percent in 2015, while the median for the bottom decile was a decline of 35 percent, according to data compiled by Bloomberg. That compares with a 39 percent median return for the corresponding top group in the Standard & Poor's 500 Index, and a median drop of 43 percent.

For many US managers, 2015 was a bad year. New York-based Einhorn's Greenlight Capital hedge fund, dropped 20 percent in 2015, only the second losing year in its almost 20-year history. Ackman's Pershing Square Holdings Ltd slumped 20.5 percent in 2015, while funds run by Fortress Investment Group LLC and BlackRock Inc were among those that closed down.

Market volatility is working against some hedge funds investing in China this year, amid a rough start for the nation's stock market. The Shanghai Composite Index is down almost 15 percent so far in 2016, making it the worst-performing primary stock gauge tracked by Bloomberg. Fears of a slowdown in China have rippled across the world, with a sell-off wiping out more than $5 trillion from global equity values this year.

Many managers, including the GH China Century Fund in Singapore, posted gains in 2015 after selling China shares to lock in gains before they collapsed mid-year, and snapped them up again before they rebounded in August.