Western Digital has given back almost all of yesterday’s big up move.
Two pieces of news yesterday:

Craig-Hallum analyst Christian Schwab upgrades Western Digital (NASDAQ:WDC) from Hold to Buy and raises the price target from $44 to $62.

Western Digital shares have sprung to life amid speculation that a corporate reorganization announced on Tuesday could be a prelude to a split into two companies, one focused on disk drives and the other on flash memory products.
Western Digital (ticker: WDC) said late Tuesday that it had created two separate business units, one focused on drives and the other on flash. The company also announced that it had hired a former Symantec and Cisco executive, Robert Soderbery , as general manager of the flash unit — and that it was looking for a leader for the hard drive business.
The company gave no indication that it planned to divest or spin either of the two businesses, but some analysts think CEO David Goeckeler may be laying the groundwork for major structural change at the company.