As promised, Carl Icahn has released his open letter to Apple Inc. (NASDAQ:AAPL) CEO Tim Cook. He posted the letter on his website, Shareholders’ Square Table.

Apple Inc. Should Make Tender Offer For Share Buybacks: Icahn

Icahn: Apple is undervalued

Unsurprisingly, Icahn started by buttering up Apple management and praising the new bigger iPhone 6 models. He also provided his firm’s projections for Apple in the coming years. He’s projecting a 25% growth rate in revenue and 44% growth rate in earnings per share for the 2015 fiscal year.

Assuming his numbers, that means Apple trading at a price to earnings per share ratio of eight times his estimates. That’s a much lower ratio than the S&P 500, which trades at a ratio of 15 times 2015 fiscal year estimates. Icahn also expects Apple to increase its earnings per share by 30% in the 2016 and 2017 fiscal years while the S&P 500 grows more slowly.

The activist investor uses these numbers to explain why he thinks Apple stock is significantly undervalued. In fact, he calls the low ratio “irrational and transient in nature,” adding that many mutual funds are still underweight on the company in their portfolios. He believes the company should be trading at a multiple of 19 times instead, which means that Apple stock should be worth $203 per share, in his view, which includes net cash.

Icahn pushes for tender offer from Apple

Just as he did last year, Icahn again called for Apple to begin a massive share buyback plan. He’s pushing for a tender offer, noting that the company has plenty of net cash to do it–$133 billion. The purpose of that tender offer would be to increase the company’s share repurchases.

The billionaire also promised not to tender his firm’s shares, no matter what price Apple gives for its tender offer. Unlike last year, when Icahn pushed for a $150 billion share repurchase, this time he isn’t giving a size, and he said that whatever method Apple management chooses to take in doing the share buyback will make him happy.