Shares of Apple (Nasdaq: AAPL), the world's most valuable technology company, rose $2.04 to $662.63, Wednesday in advance of the expected announcement of the iPhone 5 at a product introduction in San Francisco, which isn't scheduled until late morning, Pacific time.

Shares of the Cupertino, Calif., electronics company set an all-time high of $683.29 on Monday, before falling back to their current levels. Over the past year, they'be barreled past the $400, $500 and $600 marks. In the first quarter, Apple surpassed Exxon Mobil Corp. (NYSE: XOM) as the world's most valuable company.

Analysts in general have been bullish on Apple, with high estimates for the shares over the next year pegged at $1,111.