An investment vehicle for billionaire financier Carl Icahn (search) revealed Friday it owned 10 million shares in drug store chain Rite Aid Corp. (RAD) and 4.5 million shares of business software maker Siebel Systems Inc. (SEBL) as of March 31.

The investments by Icahn Management LP represent about a 2 percent stake in Rite Aid (search) and just under a 1 percent stake in Siebel Systems (search), which has been considered a possible takeover target of larger software companies.

The filing also showed the firm no longer held 449,600 shares of insurance broker Aon Corp. (AOC) as of that date and that it owned 104,560 shares of Hewlett-Packard Co. (HPQ), according to U.S. Securities and Exchange Commission (search) filings.

Carl Icahn — as an individual— also increased his stake in Ladenburg Thalmann Financial Services Inc. (LTS) to nearly 6.5 million shares from about 3.4 million shares in the first quarter a separate filing showed. That company's stock shot up, 26 cents, or almost 50 percent, to close at 79 cents a share on the American Stock Exchange Friday.

Rite Aid shares moved up 3.12 percent, or 12 cents, to close at $3.97 on the New York Stock Exchange. Siebel shares closed up 7 cents, less than 1 percent, to $9.66 on Nasdaq.