The ATS will allegedly go coupe-only after 2018.

The American sedan segment might be about to take another punch to the gut. Recent reports indicate the four-door Cadillac ATS has just entered its final model year on the market.

Though not official at this point, the information comes from internal documents uncovered by our colleagues at The Truth About Cars. VIN data lists the ATS as a coupe-only model for 2019 without any major mechanical modifications. It will carry on with a standard four-cylinder engine, an optional six-cylinder, and a range-topping twin-turbocharged V6 found under the ATS-V's hood.

While it sounds like the ATS sedan is about to get the bullet, it might not be that simple. The Truth About Cars points out auto-makers can submit information about upcoming models up to 60 days before the start of production. That means Cadillac still has plenty of time to submit data about the 2019 ATS sedan, assuming it wants to continue building the car.

Cadillac hasn't commented on the report. Its 2019 models won't arrive in showrooms until about halfway through next year so we'll have to be a little bit patient to find out what the future holds for the four-door ATS. If it's indeed getting axed, don't expect Cadillac's 3 Series-fighting model to spawn a successor before the end of the decade. The brand has previously confirmed plans to trim sedans and focus on SUVs.