AFP: Apple's stock price has climbed to $665.15 a share, pushing its market cap to approximately $623.51 billion. That not only makes Apple the world's most valuable company, it makes Apple the world's most valuable company ever. The previous record was set by Microsoft in 1999, when the Windows maker boasted a value of $619 billion.
However, some have noted that Apple isn't the most valuable company ever when you adjust for inflation. One dollar in 1999 would be worth $1.38 today. That means Apple's stock value would have to reach $853.4 billion to match Microsoft's record in adjusted dollars.