Apple Inc. stock recaptures $500 as Carl Icahn shows support, hype for new iPhones builds

The milestone came a day after billionaire investor Carl Icahn publicly expressed his support for Apple, calling the company's stock "extremely undervalued." As of Wednesday afternoon, shares of Apple were up more than $11 for the day alone.

Icahn also noted on Tuesday that he spoke with Apple Chief Executive Tim Cook in an effort to persuade him to initiate a larger share buyback. The company has already committed to spend $100 billion through 2015 on share repurchases and an increased quarterly dividend.

The support from Icahn has clearly encouraged other investors to buy in to Apple ahead of the company's Sept. 10 event. Those shareholders may see Icahn as having the ability to convince Cook to increase the buyback and add value to shares of AAPL and boost earnings per share.

The billionaire investor revealed on his official Twitter account this week that he has a "large position" in Apple. That's amounted to an investment of some $1.5 billion in the iPhone maker, according to The Wall Street Journal.

Apple's surge also comes just days after it was reported that Apple is planning to hold a media event in September to announce its next-generation iPhone. The company is also expected to debut a new low-cost iPhone with a plastic frame that could help the company capture a larger portion of the overall smartphone market.

Shares of Apple also performed well in the month of July, helping the company reclaim the title of world's most valuable, based on market capitalization. Apple and Exxon Mobil have traded places in that distinction a number of times in recent years.

While Apple has surpassed $500 as of Wednesday afternoon trading, the company's shares are still well off from its high of $702.10, reached nearly a year ago ahead of the launch of the iPhone 5.