Carl Icahn went on CNBC again yesterday where he maintained his view on Apple after earnings:

"You look for companies like this that comes around once a decade, maybe even less than that. They are just no-brainers to buy and the risk reward is just so much in your favor on that one. Because where do you see a company that literally can do 8-9 times earnings in '15 and we believe the earnings are gonna grow 30%..."

He went on to explain how a lot of funds are short Apple stock, not literally, but by being underweight compared to the index. As they compete with the index funds, they will be forced to bring that back to balance as Apple outperforms the index. It's tantamount to a short squeeze on a large scale.

Icahn wouldn't say whether he added to positions after the open letter, but said that his son Brett manages the Apple position and that he rarely vetoes his decisions.