May 6 (Reuters) - Marathon Petroleum ( MPC ) swung to a

loss in the first quarter, the company reported on Tuesday, the

latest U.S. refiner hit by lower refining margins during a

period marked by elevated maintenance and turnaround activity

across the industry.

The company said the results reflected the second-largest

planned maintenance quarter in its history.

The Findlay, Ohio-based company said refining and marketing

margin was $13.38 per barrel in the first quarter, compared to

$19.35 per barrel in the same period of 2024.

Refineries typically conduct planned maintenance-known as

turnaround activity-in the first quarter to prepare units for

the higher demand during the summer driving season.

This scheduled downtime reduces refinery utilization,

limiting the companies' ability to capitalize on margins and

weighing on quarterly performance.

U.S. refining margins, as measured by the 3-2-1 crack spread

rebounded in the first three months of 2025 after

touching multi-year lows last year, but continue to face

pressure from lingering market challenges.

Rivals Valero Energy ( VLO ), Phillips 66 and HF

Sinclair ( DINO ) also reported quarterly losses.

"We are positioned to meet summer demand as seasonal trends

are expected to improve margins and we remain constructive on

its long-term outlook," Marathon's CEO Maryann Mannen said in a

statement.

Marathon, the top U.S. refiner by volume, said quarterly

crude capacity utilization was about 89%, resulting in total

throughput of 2.8 million barrels per day (bpd), compared with

2.7 million bpd a year earlier.

The company expects total refinery throughput of 2.9 million

bpd for the second quarter.

Net loss attributable to the company was $74 million, or 24

cents per share, for the three months ended March, compared to a

profit of $937 million, or $2.58 per share, a year earlier.

Analysts on average had expected a loss of 53 cents per

share, according to data complied by LSEG.

(Reporting by Arunima Kumar in Bengaluru; Editing by Sriraj

Kalluvila)