Shares of Western Digital (WDC) led the S&P 500 Thursday with a 10 percent gain on the heels of better than expected fiscal fourth quarter earnings. The stock was TheStreet's Move of the Day. Earnings came in at $1.51 a share, compared with estimates of $1.45. Though last year, the data storage company earned $1.85 a share. Revenue totaled $3.2 billion, just shy of the $3.25 billion Wall Street expected. The company's CEO Steve Milligan said demand for the quarter was weak given softness in the PC market. However, he told analysts in an earnings call that he sees 'early signs of market stabilization,' which comes on the heels of Microsoft's (MSFT) recent launch of Windows 10. 'I am satisfied with our execution and performance in the fourth fiscal quarter in light of the weak PC market,' Milligan said. TheStreet's Scott Gamm reports from New York.