Paulson & Co., a hedge fund, has purchased a large stake in Allergan Inc; six million shares. The hedge fund is also backing a deal between the Botox maker and Valeant Pharmaceuticals Inc. The shares make the firm, which is led by John Paulson, one of the top 10 holders of Allergan shares. Allergan shares closed with a 2.3% riseat $169.07, while Valeant shares were up 4.5% at closing at $1225.94 on the NYSE.