Billionaire investor Carl Icahn reportedly acquires a significant stake in Caesars Entertainment.

Billionaire activist investor Carl Icahn has reportedly built a significant stake in US casino operator Caesars Entertainment, raising the prospect of a new conflict with the company. The size of Icahn's stake and his intentions remain unknown, with representatives for Icahn and Caesars declining to comment. Caesars Entertainment shares rose as much as 17% in response to the news.