Stocks were making small moves in a big day for blue-chip earnings. General Motors (GM) and Boeing (BA) climbed after better-than-expected reports, while Chipotle (CMG) and Yahoo! (YHOO) slipped on earnings disappointments. Valeant Pharmaceuticals (VRX) plummeted and took other biotech names down with it. The fall came after short seller Citron Research released a report claiming it has a smoking gun on the drugmaker. Ferrari (RACE) raced higher in its market debut. The luxury car maker traded at $60 a share, above its initial public offering price of $52. Fiat Chrysler's (FCAU) stake was reduced to 80% following the float. Western Digital (WDC) confirmed it has agreed to acquire SanDisk (SNDK) for $19 billion.