Publicly listed companies that are popular with U.S. hedge funds lost more money than sector rivals when stock markets tumbled in the last few months, new data from research firm show.

Hedge fund managers, who often promise strong returns in all markets, were caught off guard when stocks sold off on fears of slower growth in China, falling energy prices, and worries about a potential U.S. interest rate hike.

Some funds are nursing double digit declines, their deepest since 2008, according to the data that Symmetric will release to clients on Tuesday. Reuters reviewed the data on Monday.

David Einhorn's Greenlight Capital is off 17 percent while Larry Robbins' Glenview Capital is down 13 percent. The Standard & Poor's 500 index is off 2 percent.

"Companies with the highest concentration of hedge fund ownership are performing 6 percent worse than the sector they are in," Symmetric Managing Director Sam Abbas said.

Part of the problem could be that stocks fall more as hedge funds look to exit losing positions, creating a sort of vicious cycle, Abbas said.

The stock of Brookdale Senior Living <BKD.N>, a favorite among hedge funds, was a major loser.

In May billionaire investor Larry Robbins touted the senior housing company as one of his best ideas at the Sohn Investment Conference, saying that one of the easiest things is to bet on an aging population. He owns 11.6 million shares, making him Brookdale's seventh largest investor.

Whether people took Robbins' advice and piled in is unclear, but 43 percent of Brookdale's outstanding stock is owned by hedge funds including Barry Rosenstein's Jana Partners, Discovery Capital Management and Scopia Capital Management.

Since the presentation, Brookdale's stock has fallen 35 percent, creating pressure for Glenview whose portfolio is down double digits after a 25 percent gain in 2014.