U.S. stocks held highs through to the middle of the session, extending Tuesday's Yellen-inspired rally. Wall Street has been in a good mood since Fed Chair Janet Yellen stressed caution in raising rates on Tuesday. Crude oil spiked after U.S. inventories added 2.3 million barrels in the past week, below estimates. The smaller-than-expected increase eased investor fear over a growing supply glut both on domestic and global markets. Restoration Hardware (RH) - Get Report jumped despite issuing a weak outlook for the current quarter. Apple (AAPL) - Get Report climbed after Cowen & Co. upgraded the stock to OUTPERFORM from MARKET PERFORM. Analysts said the tech giant will benefit from an upcoming upgrade cycle wherein consumers replace old gadgets with the newest model. TheStreet's Keris Lahiff reports from Wall Street.