(Reuters) – U.S. oil refiner HF Sinclair Corp beat first-quarter profit estimates on Thursday, as margins spiked from a year earlier amid tight supplies and robust demand.

Refiners in the United States have benefited from favorable pricing and demand as global supplies remain tight after Western sanctions on Russia, while pandemic-era closures have resulted in low refined product inventories and boosted margins.

HF Sinclair, formerly known as HollyFrontier, said its gross margin jumped 87% to $23.70 per produced barrel in the first quarter.

The robust margins helped the company offset a decline in refinery throughput, or the amount of crude processed, which fell about 1.2% to 558,130 barrels per day due to maintenance activities at Puget Sound, Wood Cross and El Dorado refineries.

U.S. refiners ramped up maintenance activities during the March quarter, after high utilization rates last year to meet a rise in demand.

HF Sinclair’s refinery utilization stood at 73.5%, compared with 88.6% a year earlier.

On an adjusted basis, the Dallas-based energy firm posted a profit of $2 per share for the quarter ended March 31, compared with analysts’ average estimate of $1.52 per share, according to Refinitiv data.

Separately, HF Sinclair submitted a non-binding proposal to Holly Energy Partners (NYSE:HEP) LP to acquire all outstanding shares not owned by the company.

“We believe the proposed HEP Transaction simplifies HF Sinclair’s corporate structure, reduces costs and further supports the integration and optimization of our portfolio,” incoming Chief Executive Officer Tim Go said in a statement.

According to Refinitiv data, HF Sinclair already owns 47.16% of Holly Energy, which has a market value of $2.01 billion.