contentious

The one-time hedge fund executive now running a biotech firm at the center of a drug-pricing controversy on Monday said he has bailed from a losing bet he made on another contentious drug maker: Valeant Pharmaceuticals International Inc . On the day last week that Valeant shares plunged in response to a shortseller’s accusation of accounting irregularities, Martin Shkreli, head of Turing Pharmaceuticals, took to Twitter to say he had bought shares of Valeant while at the same time selling short the shares of rival Allergan Plc , a transaction known as a pairs trade. Onward and upward,” Shkreli tweeted, just hours after Valeant laid out a detailed defense against the accusations of accounting fraud.