Had a nice conversation with Tim Cook today. Discussed my opinion that a larger buyback should be done now. We plan to speak again shortly.— Carl Icahn (@Carl_C_Icahn) August 13, 2013So what does this mean for shareholders? Although it's a little too early to tell, it is a positive step in the right direction. I would expect that traders and investors will begin chasing the stock and that $500 per share by the end of the week wouldn't be out of the question. The stock could get especially extended if the institutional investors were caught off guard. It's easier for them to accumulate a high-profile stock like Apple when it has been stuck in the mud like it has for most of 2013. But this rapid rise over the last week, and specifically on Tuesday, could force a lot of investors to chase the name who wanted to own it under $500. In all, I don't think Icahn can be the type of "bully" with Apple, as he is toward other companies. This isn't Dell ( DELL) and he's not going to be making any takeover bids. While he's now proved he can move a mega-cap stock like Apple, I think his influences will be much less relevant than the public may be used to. In any regard, he's in the stock to make money, something that should encourage shareholders. If Apple goes the way his other plays have gone this year, investors will be very happy. -- Written by Bret Kenwell in Petoskey, Mich. Follow @BretKenwell At the time of publication, Kenwell was long AAPL in any stocks mentioned.