SCHAUMBURG, Ill. (AP) -- Billionaire investor Carl Icahn reported increasing his stake in Motorola Inc. to 7.6 percent from 6.4 percent in a filing Wednesday with the Securities and Exchange Commission.

Icahn now owns about 172.2 million shares, or a 7.6 percent stake in the cell-phone maker, based on 2.26 billion shares outstanding as of March 14.

He previously reported owning about 144.6 million shares, representing a 6.4 percent stake in the Schaumburg, Ill.-based company.

In late March, after months of investor frustration, Motorola announced plans to split its slumping handset unit from its home and networks business to create two publicly traded companies.

Then in April, Motorola ended a proxy fight with Icahn, agreeing to seat two of his nominees on its board of directors.

In return, Icahn agreed not to solicit proxies at the annual meeting, to dismiss litigation against the company and to vote his shares in support of all of the board's director nominees.

Motorola shares shed 37 cents, or 3.6 percent, to $9.89.