American billionaire Warren Buffett’s investment company Berkshire Hathaway Inc continued to buy shares in Occidental Petroleum Corp, which produces oil from shale deposits, increasing its share to 19.4%.

Berkshire bought 1.9 million shares for more than $100 million on July 14-15, according to documents sent to the Securities and Exchange Commission (SEC). The price of securities ranged from $56 to $59 per share.

Berkshire currently owns 181.7 million shares of Occidental with a combined value of about $11 billion, the documents say.

Thus, at present, Buffett’s investment company is the largest shareholder of Occidental. Berkshire’s stake is approaching 20%, after which it will be able to include Occidental’s results in its financial statements.

Experts expect that NK will make a profit of about $10 billion this year.

Market participants continue to speculate that Buffett may be interested in buying the entire company. The remaining stake of just over 80% will cost Berkshire about $60 billion at a price per share of $80, writes Barron’s.

Occidental shares rose 0.8% in Monday’s additional trading. Since the beginning of the year, the company’s capitalization has more than doubled to more than $55 billion.