Money managers are having trouble picking winners. But they sure can pick losers. Take Whitney Tilson, who makes money by betting on stock declines — or short selling. Just last week he closed out his bet against Lumber Liquidators Holdings Inc., riding it from about $100 to less than $20. He’d helped trigger the stock collapse when he publicized suspicions in 2013 about the company’s wood flooring. Then there was this autumn’s takedown of Valeant Pharmaceuticals International Inc. by Andrew Left and his Citron Research. Valeant, which had been a punching bag for both politicians and Bronte Capital’s John Hempton, plunged when Left compared […]