NEW YORK (CNNMoney.com) -- Financier Carl Icahn increased his stake in Time Warner since he dropped his proxy battle to shake up the media conglomerate, according to his latest filing with the Securities and Exchange Commission.

According to the filing Monday by Icahn Management LP, Icahn's firm owned 49.6 million shares of Time Warner (Charts) as of June 30. That's up 8 percent from the 45.8 million shares he held as of March 31, as reflected on his previous filing.

Carl Icahn has increased his stake in Time Warner.

The latest filing puts Icahn's stake in Time Warner at 1.2 percent of shares outstanding.

Icahn led a group of Time Warner shareholders who pressed the No. 1 media conglomerate to be broken up into four separate companies and increase its share repurchase plans in an effort to raise its stock price. He dropped those efforts Feb. 17 after the company agreed to some of his demands including increasing its stock buyback plan and cutting up to $1 billion in costs by the end of 2007.

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Other companies where Icahn added to pre-existing holdings during the quarter include natural gas pipeline owner Williams Companies (Charts), where his shares held soared 1680 percent to 4.8 million shares, as well as car rental company Cendant (Charts), where his holdings increased 155 percent to 6.1 million shares.

Companies new to his portfolio in the most recent filing include security software firm Symantec (Charts) and insurer Cigna (Charts).

His stakes in all four of those companies were near the $100 million mark as of June 30, which gives him between a 0.6 and 1 percent stake in each company as of that date.

In a separate filing Monday, Icahn disclosed that he has "not yet made a determination" on the invitation from ImClone Systems (Charts) to join its board.

Icahn also said that a group of investors he is leading has raised its stake in the New York-based biotechnology company to 11.68 percent of its outstanding shares. Shares of ImClone plunged last week when it disclosed it had not found a buyer following a six-month search and that it planned to remain independent.

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