Occidental Petroleum (OXY) - Get Report shares traded higher Friday after Carl Icahn lost a court battle to gain access to records linked to the group's $38 billion takeover of Anadarko Petroleum (APC) - Get Report  , a deal the billionaire activist investor has consistently challenged.

Delaware Chancery Court vice chancellor Joseph Sights said Icahn's request for the records failed to demonstrate how it would aid his planned proxy fight against company management, and could be a blow to his plans to upend the Anadarko deal, which he has described as "one of the worst I've ever seen." Icahn had asked for the records in order to determine "whether the actions of the directors and management were just serious mistakes or whether they represented knowing intentional breaches of fiduciary duty" in executing the $38 billion deal.

Separately, a 13-F filing published last night with the U.S. Securities and Exchange Commission late Thursday indicated that Warren Buffett's Berkshire Hathaway (BRK.A) - Get Report investment group has built a 7.5 million share stake in Occidental after supporting its Anadarko takeover earlier this year.  

Occidental shares were marked 4% higher in early trading Friday to change hands at $39.31 each, a move that still leaves the stock nursing a year-to-date decline of around 36%.

Last week, Icahn trimmed his stake in Occidental to around 23 million shares but vowed to run a proxy fight against the board next year, calling the company's actions "specially reprehensible since management repeatedly pledged that it would not engage in risky M&A and would maintain a prudent balance sheet."

Earlier this month, Occidental told investors it will slash its capital spending by around 40%, pegging 2020 outlays at around $5.4 billion and those in 2021 at $6.6 billion as it moves towards trimming debt linked to the Anadarko acquisition.

"We are very focused, we are very intense on ensuring that we get the asset sales done because we believe we must get our debt down, that's an internal target," CEO Hollub told investors on a conference call Tuesday. "We talk about it every day."

"In my opinion, OXY's acquisition of Anadarko is nothing more than a massive $57 billion levered bet on the price of oil - and the bet is failing," Ichan wrote last Friday. "Interestingly, although OXY has dropped 42% since April, oil has only dropped 12%."

"We believe this is because Wall Street has completely lost faith in Hollub and her Board and has concluded, in my view, that Hollub and her Board will put their interests far above the best interests of OXY's stockholders," he added. "Once the institutional investors have soured on a company, it is extremely hard to regain their confidence."