Talisman Energy Inc. stock spiked Tuesday morning to $13.83 after activist investor Carl Icahn revealed he has bought a 5.97 per cent stake in the company.

Icahn, a powerful U.S. investor and hedge fund manager, tweeted his interest in the Calgary-based oil and gas producer Monday night, adding that he has plans for getting more value out of the company.

Talisman shares were up 4.8 per cent to $13.15 on the Toronto Stock Exchange on Monday and but by the close of trading Tuesday sank back to $12.89,well off their peak.

"May have conversations with mgmt re strategic alternatives, board seats, etc.," Icahn tweeted.

Icahn, who recently gave up a bid to take over Dell, has a mixed reputation as a corporate raider and as an investor who boosts share performance. He recently began pressuring Apple to return more of its earnings to shareholders.

Icahn has suggested he may take a seat on the Talisman board of directors. In a U.S. regulatory filing, he said he bought 61.5 million shares of Talisman, believing they were undervalued.

Icahn wants to 'enhance shareholder value'

"The reporting persons intend to have conversations with members of the issuer's management to discuss strategic alternatives which may enhance shareholder value, including, among other things, asset sales or potential corporate restructuring,” his filing said.

Talisman is led by Hal Kvisle, a former chief of pipeline company TransCanada Corp., who replaced John Manzoni as CEO about a year ago.

Under Kvisle's leadership, Talisman, which has assets all over the world, has reduced its workforce and focused its capital on production in the Americas and Southeast Asia. It has moved out of higher-risk production areas, such as Peru, and put assets in the North Sea up for sale.

However, it reported an operating loss of $27 million for the second quarter of this year.

Talisman response

Talisman spokeswoman Phoebe Buckland said the company is engaged in a strategy that will position it as "highly competitive player" in its core areas.

"The aim of this strategy is to significantly improve total shareholder returns and near-term profitability and is in the best interest of the company and all its stakeholders," Buckland said  in an email statement.

"We appreciate constructive input from shareholders and take their views seriously. We are committed to acting in the best interests of the company and give due consideration to constructive recommendations for strategies or actions that have the potential to increase shareholder value."