For years it was little more than a rumor whispered among BMW enthusiasts: that at some point in the company’s history, someone inside the hallowed halls of M GmbH had built a drop-top M5. Now, BMW has officially confirmed it — and revealed why the world never got to see it.

The car in question was based on the E34 generation M5, and it was shown publicly for the first time to a select group of journalists in 2009 at an event marking 25 years of the BMW M5. BMW confirmed that the convertible had been developed as a genuine production-ready model, featuring two lengthened front doors and seating for four occupants — a proper grand touring machine in the M5 spirit.

Priced at $70,000 in the 1990s

The E34 M5 Convertible one-off with a soft roof

The price had been set at £50,000, BMW had booked stand space at the Geneva Motor Show, and a launch was imminent. Then, just one week before the event, the plug was pulled.

The reason? BMW feared the M5 cabriolet would cannibalize demand for its mainstream 5 Series convertible — and more critically, harm sales of the highly profitable drop-top 3 Series. A product planning concern, in other words, killed what could have been one of the most exciting open-air cars of its era.

Imagine That Sound With The Top Down

The E34 M5 Convertible side view

It’s a decision that feels all the more painful when you consider what was under the hood. The E34 M5 was powered by a 3.8-liter inline-six producing 340 horsepower and 295 lb-ft of torque, sent to the rear wheels through a six-speed manual gearbox. The idea of experiencing that sonorous engine with the sky overhead is, to put it mildly, tantalizing.

The M5 convertible wasn’t the only extraordinary machine BMW’s skunkworks conjured up during the E34 era, either. Engineers also reportedly shoehorned the 6.1-liter V12 from a McLaren F1 into an E34 M5 Touring — proof that the engineers inside M Division had no shortage of ambition, even when the boardroom had other ideas.

It’s one of automotive history’s great “what ifs” — a car that existed, was ready, and was denied to the world at the last moment. BMW has confirmed the story. The M5 convertible remains, forever, the car that almost was. See more photos below.