Billionaire investors Barry Rosenstein and Daniel Loeb's hedge funds lost more money in February as both managers were hit by volatile markets shaped by fears about slower growth and uncertainty over how the Federal Reserve will react.

David Einhorn's Greenlight Capital was one of the first funds to report good news to investors, telling clients that he gained 1.9 percent in February which left the fund up 3.3 percent for the first two months of 2016, a source said.

Rosenstein told investors that his Jana Partners fund lost 3.6 percent in February, leaving it down 7.3 percent. His Jana Nirvana fund lost even more money, dropping 5.37 percent to be off 10.9 percent, a second source said.

For Rosenstein, part of the trouble is surely related to pharmaceutical company Valeant Pharmaceuticals International Inc whose shares tumbled 24 percent in February when the company said it was being investigated by the Securities and Exchange Commission and its chief executive returned abruptly from an extended medical leave.

Jana had gotten back into Valeant late last year, according to a regulatory filing, along with a number of other big name investors who reasoned that the stock price's fall sparked by questions about its accounting and business practices had been overdone.

Loeb meanwhile reported that his Third Point Partners fund lost 0.4 percent, leaving it down 4.8 percent for the year, a third source said. Loeb had been telling clients that he was positioning himself more defensively by taking on fresh short positions, something that may have hurt him as the market came back late in February.

Most funds are still calculating their numbers and will start sending returns to clients later this week. The average hedge fund has lost 3.13 percent this year, data from Hedge Fund Research show.

For Einhorn it was a long awaited turnaround after having been one of last year's biggest losers with a 20 percent loss, the first decline for his fund since losing money during the financial crisis in 2008.

Bets on retailers Macys Inc and Dillard's Inc have helped Einhorn's fund so far this year.