Apple has been eying Exxon Mobil's market cap since the Cupertino, CA-based company passed Microsoft last year to become the world's most valuable tech stock and the world's second most valuable company. On Monday, the first day of trading in 2011, Apple passed $300 billion in value, but Exxon Mobil's lead is increasing, not shrinking.
Apple's market capitalization, which is the number of shares x share price, was at $302.5B in late morning PST trading. Meanwhile, Exxon Mobil had increased its lead to some $73 billion, with its market cap calculated to be $375.9B.
Naturally, these numbers go to and fro with the tide of the stock market, but last year Apple had narrowed the distance to within $50 billion, so despite its obvious gains in price, the high price of oil seems to mean Apple isn't going to pass Exxon Mobil in valuation anytime soon.