Carl Icahn quietly upped his stake in Apple to $4.4 billion by Philip Elmer-DeWitt @FortuneMagazine May 16, 2014, 9:48 AM EST E-mail Tweet Facebook Google Plus Linkedin Share icons FORTUNE — Give Carl Icahn credit. When he was lobbing tweets and televised sound bites at Apple’s AAPL board of directors last year — demanding, at one point, an “immediate” $150 billion stock buyback — he also insisted he was not looking for a quick gain. “There is nothing short term about my intentions here,” he wrote in an open letter to CEO Tim Cook in October. True to his word, he has not only held on to the Apple shares he bought last year, but has been quietly picking up even more. According to an SEC Form 13f filed Thursday Icahn Enterprises bought another 2.8 million shares of Apple in the first quarter of 2014. Icahn now owns 7.5 million shares — just under 1% of Apple’s outstanding stock. His shares are worth, as of Thursday’s close, $4.4 billion. In the end, Icahn got nearly everything he asked for. In April, Apple announced that it had accelerated its stock buyback program. The company now expects that by the end of 2015 it will have returned $130 billion to shareholders — not the full $150 billion buyback Icahn wanted, but in the ballpark. Meanwhile we estimate that the $3.7 billion he’s invested in Apple since last summer has grown by roughly $700 million — a 19% return in the space of seven months. Not bad. UPDATE: We see that Greenlight Capital’s David Einhorn, who sued Apple last year as part of a similar effort to “unlock” the value of the company’s cash holdings, lowered his stake by 404,000 shares. By the end of the quarter, Greenlight held just under 2 million shares of Apple.