As natural as it is to assume a hyper car manufacturer to be participating in races and transferring the technology to its road cars, this is not the case with Koenigsegg. According to Drive.com Koenigsegg nearly created a race car to compete at Le Mans.
There are not many details, but apparently back in 2007 the company developed a car named the Koenigsegg CCGT built on the CCR and imagined from the original CC prototype. They debuted the CCGT at the 2007 Geneva Motor Show. This car had a 5.0-liter V-8 tied to a sequential gearbox. The production car had a supercharged 4.7-liter V-8 with a power output of over 800 horsepower, but in order to meet class regulations that power was significantly cut.
The Koenigsegg CCGT was intended to race the GT1 class at Le Mans, and they designed it almost too well - due to the carbon fiber composition of the car, it was originally too light and required ballast added to hit the minimum weight. The post calls it a "dynamic, super-stiff car that would have been very competitive."
Koenigsegg created just one CCGT, as they were more focused on building their consumer business at the time, and two months after the first shake down runs the regulations of the GT1 class changed, making the CCGT ineligible. The carbon monocoque which is a staple of Koenigsegg engineering even to this day was no longer allowed. Additionally, production number requirements jumped from 20 cars in multiple years to 350 cars per year, officially disqualifying the small-batch car from ever driving at the top racing circuit.