U.S. stocks were mixed as a slew of earnings reports kept investors busy. Around 15 percent of S&P 500 companies have reported so far with industry titans including General Motors (GM) - Get Report and Biogen (BIIB) - Get Report out Thursday morning. SunEdison (SUNE) has filed for Chapter 11 bankruptcy protection after weeks of reports it was on the verge of doing so. The solar energy company secured $300 million in debtor-in-possession financing while it restructures. Stanley, Black & Decker (SWK) - Get Report jumped after boosting earnings and revenue in its recent quarter. Southwest Airlines (LUV) - Get Report reported a 13 percent increase in first-quarter profit thanks to cheaper fuel costs. Fuel and oil expenses fell nearly 3 percent over the recent quarter. TheStreet's Keris Lahiff has details from Wall Street.