UPDATE 1-Ackman's Pershing Square ends 2015 with 20.5 pct drop
(Adds details on other funds' returns, quote)
By Svea Herbst-Bayliss
BOSTON Jan 5 (Reuters) - Billionaire investor William Ackman's Pershing Square Holdings hedge fund ended 2015 with a 20.5 percent loss after Valeant Pharmaceuticals, a top holding, was battered in the second half of the year.
That put the closely watched activist investor into the same league as rival billionaire hedge fund manager David Einhorn, whose Greenlight Capital finished also ended the year with a 20 percent drop, according to investor updates seen by Reuters.
For Ackman, the drop marks the worst performance in his firm's 11-year history. For Einhorn, it was the first down year since his fund lost 23 percent in 2008, when many hedge funds were in the red during the financial crisis.
Pershing Square Holdings, one of several portfolios run by the Ackman's $14.9 billion hedge fund, ended December nearly flat with a 0.3 percent gain for the month, the update showed.
Einhorn's roughly $11 billion fund posted a similar return, inching up 0.4 percent in December, the update showed.
Pershing's loss had been expected since Ackman had been hurt by accelerating falls in big name stocks since the summer months. But it also illustrates just how volatile the activist investor's returns can be after he scored a 40 percent gain in 2014 when he ranked among the industry's best performers.
Valeant hurt Pershing Square while Greenlight was hit by bets on Consol Energy and Micron Technology. Continued...