Hedge fund titan Carl Icahn announced via Twitter that he had purchased a stake in the oil and gas exploration company Talisman Energy.
Though Talisman's stock has been virtually flat since late 2011, the share price spiked 6 percent in extended-hours trading.
"Disclosed approx 61 million share position in Talisman Energy. May have conversations with mgmt re strategic alternatives, board seats, etc.," Icahn's tweet said.
According to a filing with the SEC, he bought 61,554,602 shares, or a 5.97 percent stake, for $277 million.