Warren Buffett's Berkshire Hathaway on Friday received regulatory approval to buy up to 50% of oil behemoth Occidental Petroleum.

Shares of Occidental soared 10% following the news to close at $71.29 apiece, making their 2022 gains more than 145%.

On July 11, Berkshire filed an application with the Federal Energy Regulatory Commission to purchase more of the oil company's common stock in secondary market transactions. The conglomerate said that a maximum 50% stake wouldn't hurt competition or diminish regulatory authority.

Carlos Clay, acting director of the division of electric power regulation, granted the permission Friday, saying authorization was "consistent with the public interest."

The conglomerate has already pushed its Occidental stake to high milestones this year. Berkshire currently owns 188.5 million shares of Occidental, representing a 20.2% position.

Berkshire is also the owner of $10 billion of Occidental preferred stock, and has warrants to buy another 83.9 million common shares for $5 billion, or $59.62 each. 

Friday's news fueled speculation that Buffett might be willing to purchase the whole firm.

"He will likely continue to buy as much as he can get below $70 or $75. If you own 30% or 40% and would like to buy it out at $95 or $100, you saved a lot of money," said Cole Smead, president of Smead Capital Management and a Berkshire shareholder. "This stock trades like a casino. The market is giving him all the stock he wants."

David Kass, a finance professor at the University of Maryland's Robert H. Smith School of Business, said an acquisition down the road is likely.

"I think it is likely that Buffett will buy the whole thing eventually. The 50% limit may have been set to receive FERC approval for a non-controlling stake," Kass said. "He clearly plans to purchase additional shares. So far, his maximum purchase price has been $60.37 per share."

Some speculated that Berkshire and Occidental had been in communication about the potential move to increase the stake to up to 50%.

"He has always said he would only do friendly deals, so that he may have agreed with the OXY board on that limit," said Bill Stone, CIO of The Glenview Trust Company and a Berkshire shareholder.