A GMC Sierra Denali truck. GM paid nearly $90 million in fines for 2016 and more than $38 million for 2017. (Woohae Cho/Bloomberg News)

General Motors Co. and Stellantis NV paid a combined $363 million in civil penalties for failing to meet U.S. fuel efficiency standards dating back to the Trump administration, according to filings with federal regulators.

Stellantis paid more than $123 million in January for missing the mark with its 2018 model year lineup and in excess of $112 million in May for falling short in the 2019 model year, according to documents posted June 2 on the National Highway Traffic Safety Administration’s website. In December, GM paid nearly $90 million for 2016 and more than $38 million for 2017.

“This reflects past performance recorded before the formation of Stellantis, and is not indicative of the company’s direction,” said Eric Mayne, a Stellantis spokesman. Stellantis was formed in 2021 from the merger of Fiat Chrysler and France’s PSA Peugeot.

Stellantis has paid fuel economy-related fines in recent years but GM’s decision to pay a fine is a first as it had previously relied on regulatory credits it purchased from other automakers to meet the fleetwide requirements.

GM said in a statement that it expects to use a mix of credits and fine payments to meet stricter fuel economy mandates as it works toward a goal of an all-electric lineup by 2035.

The Biden administration increased penalties last year for noncompliance with federal fuel economy rules, prompting these retroactive payments. For 2019 to 2021 models, the penalty rose to $14 from $5.50 for every tenth of a mile per gallon that vehicles exceed the standard. The rate rose to $15 for 2022 models.

The revised rules under Biden require carmakers to raise average fleet fuel efficiency by 8% annually for the 2024 and 2025 model years, and an additional 10% for 2026. By then, the average must be at least 49 miles per gallon under the agency’s testing regime, though actual results for motorists will likely be closer to 39 or 40 mpg.

The industry’s current fleet average is slightly more than 25 mpg in real-world driving. Manufacturers that fail to meet the tougher requirements face civil penalties like the fines paid in recent months by GM and Stellantis.