U.S. technology giant Apple on Monday became the most valuable company of all time, stock numbers indicated. While share prices at Facebook flounder, Apple\'s share price rose to $664.74, which put the company\'s total worth at $623.1 billion, just ahead of Microsoft Corp.\'s record of $620.6 billion, Financial Times reported. Microsoft is now worth $257.6 billion, far less than its own record, which was set in 1999. Apple has also left ExxonMobil in the dust. It surpassed ExxonMobil in market capitalization in August 2011 to become the most valuable company. ExxonMobil is currently worth $406 billion. Apple shares are riding high not just on past laurels, but on anticipation of a new iPhone, a smaller iPad that will compete with Amazon\'s Kindle Fire and on rumors it is developing products to interface digital electronic with home entertainment, specifically television. Stock values at Facebook, meanwhile, hit a new low Monday. Facebook went public in May with stock valued at $38 per share. The current value is under $20. \"There is no right price for Facebook shares, because nobody understands what their earnings power is. It was a guess at $38, and it\'s a guess right now,\" Michael Pachter, a market analyst at Wedbush Securities told Financial Times.