Stocks suffered losses Wednesday as the biotech sector sold off. Boeing (BA) helped to minimize the Dow's fall after a better-than-expected third quarter. Valeant Pharmaceuticals (VRX) recovered from losses of more than 40% after the company defended its accounting practices. Short-seller Citron Research had accused the drugmaker of fudging sales numbers. Billionaire investor Bill Ackman also disclosed that he had purchased an additional two million shares during the selloff. KLA-Tencor (KLAC) jumped after larger rival Lam Research (LRCX) agreed to buy the chipmaker for nearly $11 billion. The deal is the latest in a sector coping with slowing growth and increasing expenses.