LAS VEGAS (AP) — Activist investor Carl Icahn has upped his stake in casino giant Caesars Entertainment.

The billionaire, who is seeking fundamental changes in the Las Vegas-based company, on Monday disclosed in a securities filing that recent stock purchases now put his stake at 17.75 percent.

The filing with the Securities and Exchange Commission shows Icahn-controlled hedge funds purchased 15 million shares for $126.75 million.

Icahn revealed last month he had a 10 percent stake in the company and wanted changes including board representation and a say on who will be the casino operator's next CEO. He also said he wanted to put the company up for sale.

Caesars has since replaced three members of its 12-person board with directors chosen by Icahn. He has said the company has underperformed rivals.