General Motors celebrated being the world’s largest carmaker for the 76th straight year in 2007. It was sitting on $25bn in cash. Eighteen months later, it was bankrupt.

The automotive industry is among the most capital-intensive in the world: If the economy sours, assets turn into liabilities overnight as factories churning out thousands of cars begin to haemorrhage cash. So when toxic mortgage securities blew up in 2008, causing a recession, banks performed terribly — but carmakers fared even worse.

That is what makes auto consultants at Bain so worried. They fear that carmakers are about to be hit with a one-two punch: first, they project a US recession in the next 12 to 18 months. Then, increasing numbers of baby boomers will retire, causing a structural decline so big that, they warn, US car sales could shrink from more than 17m last year to just 11.5m by 2025 — the same level seen in 2008-09, which caused GM and Chrysler to go bankrupt and Ford to suffer a $14.6bn loss.