Vicki Hollub, CEO, Occidental Petroleum Mary Catherine Wellons | CNBC

Occidental Petroleum on Sunday put a revised buyout offer in front of Anadarko Petroleum, offering to pay shareholders in mostly cash as it seeks to derail Chevron's acquisition of the international oil and gas driller. Occidental is still offering to buy Anadarko for $76 a share but would now pay 78% in cash and 22% in stock. The $57 billion transaction was initially structured as a 50-50 cash-and-stock deal when Occidental first made its public bid for Anadarko nearly two weeks ago. Anadarko agreed to sell its business to Chevron last month for $65 a share in a 75% stock and 25% cash deal worth $50 billion including debt. Anadarko's board of directors resumed negotiations with Occidental last week after determining the rival bid could be superior to Chevron's offer. Occidental says the revised offer creates immediate value and makes it more certain the deal will close.

By offering more cash, Occidental will no longer have to seek approval from shareholders to purchase Anadarko. The risk of Occidental shareholders voting down the purchase created uncertainty that Occidental's management could bring the buyout over the finish line. "Our revised proposal and merger agreement represents our comprehensive response to all points that your counsel has raised with ours over the course of the past week," Occidental CEO Vicki Hollub said in a letter to Anadarko's board of directors. Hollub revealed in the letter that counsel for Anadarko's board requested three seats on Occidental's board of directors. Occidental's new offer does not include that provision because the improved bid does not warrant giving up the three seats, she said. Earlier on Sunday, Occidental announced it had reached a deal to sell Anadarko's African assets to French oil major Total for $8.8 billion. That would achieve most of Occidental's goal of divesting $10 billion to $15 billion in assets as part of the buyout. The announcement followed a commitment by Warren Buffett's Berkshire Hathaway last week to invest $10 billion in Occidental to help fund the Anadarko buyout. Some investors and analysts, including CNBC's Jim Cramer, have criticized the sale of preferred stock to Berkshire because it comes with a steep 8% annual dividend.