SandRidge Energy Inc. (NYSE: SD) said April 9 it would evaluate any offer to buy the company from top shareholder Carl Icahn after the hedge fund manager said he could pay cash to buy the U.S. shale oil producer.

One of the best known of the hedge fund world's aggressive activist players who seek major changes in company strategies, Icahn has been railing against the Oklahoma-based company's management for months.

In a statement on April 9, SandRidge said that it would look at alternatives to its current strategy and would also evaluate "credible" offers for the company, including any offer from Icahn Capital.

"To date, Icahn Capital has rejected SandRidge's offer to participate in this process on the same fair basis as other interested parties," it said.

Icahn did not immediately return a request for comment.

SandRidge shares rose about 3.7% in midday April 9 trading. They have fallen nearly 15% since Icahn reported his stake on Nov. 21.

Last week Icahn said he planned to nominate directors who would push for a sale of SandRidge and said he was willing to make an all-cash offer to buy the company in a formal process seeking a buyer.

SandRidge said it had offered Icahn the opportunity to submit qualified, independent candidates for the board's consideration "on more than one occasion" adding that none had been put forth.

The deadline for shareholders to propose board nominees is April 16.

SandRidge has made changes in recent months after some prodding by Icahn. In February, it ousted both its CEO and CFO. Icahn, who holds a 13.5% stake, also persuaded SandRidge to back out of a $746 million deal to acquire Bonanza Creek Energy Inc. (NYSE: BCEI) last year.

SandRidge came out of bankruptcy in late 2016, overcoming opposition from shareholders who had accused the oil and gas producer of misrepresenting its value.

SandRidge had previously rejected Icahn's demand to replace two directors and the removal of a "poison pill" measure preventing individual shareholders from amassing more than a 10% stake in the company's stock.

Icahn last month persuaded Newell Brands Inc. to appoint four directors to its board, and before that opposed Xerox Corp.'s plan to sell itself to Fujifilm Holdings.