Shares of Apple (NYSE: AAPL) briefly rose Tuesday to push the company's market capitalization to a record $501 billion.
Later, the shares closed at a record $536.41, up $9.65 or 1.8 percent, bringing the market capitalization to $499.2 billion.
The valuation leaves the Cupertino, Calif.-based electronics, computing, smartphone and entertainment provider as the world's most valuable company.
No. 2, ExxonMobil, the No. 1 U.S. energy company, closed at $87.14, down 9 cents, valuing the Houston-based company at $412.5 billion.
While overall U.S. markets also surged Tuesday, Apple shares gained momentum from its cult-like following when the company sent out invitations to the long-awaited introduction of the iPad 3 tablet next Wednesday.
Apple has sold about 55 million copies of the iPad and iPad 2, so a refreshment has long been anticipated. Apple's Asian manufacturers, mainly Taiwan's Hon Hai Precision Industries, have been working to build inventory for the new products.
Being No. 1 in value in technology can be transitory. Microsoft, Intel and Cisco Systems were all the world's most valuable companies at one point before losing the crown. Microsoft is now valued around $267 billion, Intel at $136 billion and Cisco at $109 billion.