Apple on Monday became the most valuable company in history after a surge in its stock price, beating the record set by Microsoft in December 1999.

Apple's stock price topped 660 U.S. dollars per share, pushing the company's market capitalization up to 619 billion dollars. The record was previously kept by Microsoft, whose market value peaked on Dec. 30, 1999 with 618.89 billion dollars.

However, accounting for inflation, Microsoft still retains the title by a margin. According to technology news site MacRumors, Microsoft's 618.89-billion-dollar market capitalization in December 1999 would be equivalent to roughly 842.5 billion in today's dollars in inflation-adjusted terms. Microsoft is now worth 257 billion dollars.

Apple is expected to introduce iPhone 5 next month and a smaller and cheaper iPad, which has propelled the company's stock to new highs recently.