The 13F filing of Carl Icahn with the Securities and Exchange Commission (SEC) showed that his portfolio has a market value of $21,515,822,000 for the second quarter that ended July 31 of the current fiscal year.

Carl Icahn

Carl Icahn’s newly acquired stakes

During the period, the activist investor’s Icahn Capital LP acquired stakes in 11,845,167 shares of Navistar International Corp (NYSE:NAV). Icahn also acquired 678, 203 shares of Voltari Corp (NASDAQ:VLTC).

Icahn significantly boosted his stake in Dell Inc. (NASDAQ:DELL) from 7 million shares in the previous quarter to more than 150 million shares worth over $2 billion.  He also increased his stake in Nuance Communications Inc. (NASDAQ:NUAN) from 3,812,000 shares in the first quarter to 31,547,631 shares worth $552,845,000. Icahn is expected to launch activism against the speech recognition and digital imaging company.

Yesterday, Icahn revealed that he bought a large long position in Apple Inc. (NASDAQ:AAPL), and spoke to the tech giant’s CEO Tim Cook regarding a bigger shares buy back to boost the stock. According to the activist investor, the stock is “extremely undervalued.” Since his disclosure, the stock price of the iPhone and iPad maker rose to as much as $504.25 per share today.

Bill Ackman’s newly acquired stakes

On the other hand, Icahn’s fellow activist investor and rival Bill Ackman of Pershing Square Capital Management acquired 10,095,708 shares of Air Products & Chemicals, Inc. (NYSE:APD) worth $924,464,000 in the second quarter.

During the period, Ackman reduced his stakes in General Growth Properties Inc (NYSE:GGP) by 6,944,555 shares, Matson, Inc. (NYSE:MATX) by 2,831,072 shares, and The Procter & Gamble Company (NYSE:PG) by 19,006,759 shares, but he also has a call option to acquire 24,042,400 shares of the company. Ackman sold out his entire stake in Mondelez International Inc (NASDAQ:MDLZ).

Over the past few days, Ackman became a center of media discussions after he demanded to the board of J.C. Penney Company, Inc. (NYSE:JCP) to expedite the search for a new CEO to replace Mike Ullman. He also wanted to fire the company’s chairman, Thomas Engibous. The board rejected his demands and called it disruptive and counterproductive. Ackman resigned as director of the board of the embattled department store chain after the boardroom brawl.