Occidental Petroleum, the U.S. oil producer that’s 28% owned by Warren Buffett’s Berkshire Hathaway, is due to report earnings on Tuesday. It hasn’t been a great year for the company.

Occidental Petroleum is a big producer in the Permian Basin.

Its stock has lost 21% over the past 12 months and closed Friday at $48.06, about 6% above its 52-week low, according to Dow Jones market data. Slumping crude prices, as well as pledges by President Donald Trump to raise energy production and keep oil prices low, have been weighing on the shares. West Texas Intermediate prices are more than 10% lower than a year ago.

Occidental boasts a strong position in U.S. shale oil production, a sector that Trump wants to encourage. But its purchase of rival Anadarko in 2019 has left it with a large overhang of debt. It has added to its portfolio since, completing the acquisition of CrownRock last year.

Occidental’s earnings are closely tied to the price of crude. It reported output of 1.4 million barrels of oil equivalent a day in the third quarter. Even if operations performed well in the last three months of the year, profit would be hit by weaker selling prices.

For his part, billionaire investor Buffett is keeping the faith. He added to his stake this month and now holds about 265 million shares, filings with regulators showed last week. Buffett’s share of the company is now worth about $13 billion. 

Analysts expect Occidental to report earnings per share of 68 cents, down from 74 cents a year ago and $1.00 in the third quarter, according to FactSet. Revenue is expected to fall to $6.98 billion from $7.17 billion in the third quarter. A year earlier, revenue was also $7.17 billion.

Among the 30 analysts surveyed on FactSet, 19 give Occidental a Hold rating, 9 give it a Buy, and 2 say Sell. The earnings are due after the close on Tuesday.