The LMH concept emerged after Audi and Porsche departed the FIA World Endurance Championship following the 2016 and 2017 seasons respectively, compounded by the Volkswagen emissions scandal and rising hybrid programme costs in the LMP1 category. The ACO began discussions aimed at reducing expenses for the next top-level prototype generation, targeting approximately 25 million euros — a 75% reduction from existing manufacturer spending. In June 2018 the FIA confirmed the new prototype regulations would employ "design concepts based on hypercars," with Toyota, Ford, McLaren, Aston Martin, and Ferrari participating in roundtable discussions. Scuderia Cameron Glickenhaus became the first manufacturer to commit officially, on 25 July 2018.
Initial 2018 specifications called for a 980 kg car combining a 520 kW combustion engine with a 200 kW front-axle electric motor for 700 hp total, with two seats and manufacturer obligations to lease hybrid systems to privateer teams. On 5 December 2018 the FIA published the technical rulebook mandating production-based powertrains and a minimum of 25 road cars, effectively excluding non-OEM constructors such as Oreca and Dallara. Regulations were revised on 7 March 2019 to permit race cars derived from road-going hypercars, eliminating movable aerodynamic devices and extending the target lap time from 3:20 to 3:30. In May 2020 maximum power was reduced from 585 kW to 500 kW and minimum weight adjusted to 1,030 kg. Aston Martin postponed its programme in February 2020 after the announcement of the joint ACO-IMSA LMDh rules.
In 2021, shortly after Peugeot revealed their 9X8 hypercar, IMSA and the ACO announced convergence of their respective rulesets, creating unprecedented commonality between North American and world championships. The unified top class carries different names: "Hypercar" in the FIA WEC and "Grand Touring Prototype" in IMSA. From 2023, Le Mans Hypercars became eligible to compete in the IMSA SportsCar Championship alongside LMDh vehicles. In 2025 the class gained eligibility for the Asian Le Mans Series with customer teams and Pro/Am configurations, effective from the 2026/27 season.
The class is restricted to four-stroke petrol engines with no displacement limit; maximum combined power output is 500 kW (670 hp). For production-based engines the block and head castings must originate from the base engine; the crankshaft may only be 10% lighter than original specification. The hybrid Motor Generator Unit (MGU-K) is capped at 200 kW and may only deliver positive torque to the front wheels above Balance of Performance speed thresholds. Movable aerodynamic elements remain prohibited. Minimum weight is 1,030 kg; maximum length 5,000 mm; maximum width 2,000 mm; maximum wheelbase 3,150 mm.
Current competing manufacturers include Toyota (GR010 Hybrid), Ferrari (499P), Peugeot (9X8), Aston Martin (Valkyrie AMR-LMH), Glickenhaus (SCG 007 LMH), Vanwall (Vandervell 680), and Isotta Fraschini (Tipo 6 LMH-C).
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