A takeover is on the table, there's not been an official bid yet
You can see the appeal of a tie-up, together the companies would account for 1 in 6 cars bought in Europe but the fact that news of the talks has leaked may make a deal harder to do.
I've seen an email from the American CEO of General Motors to British workers.
In it Marry Barra tries to reassure. "Agreement is NOT assured," she writes. "Please don't let this become a distraction".
The Unite Union is distracted. In fact it's gone apoplectic - accelerating from shock to fury in less than seven seconds. The concern is a takeover would trigger substantial job losses.
"Let me be clear, we have no intention off allowing Luton or Ellesmere Port to close," Len McCluskey, the Unite leader, told ITV News. He wants the government to intervene.
The Business Secretary, Greg Clarke, is similarly unsettled.Tonight he called GM's President to "raise concerns". Clark and McCluskey are meeting tomorrow morning to discuss what happens next.
The reason for all this anxiety is General Motors European business - which owns the Vauxhalll and Opel brands - has lost money every year for 16-years. In total £15bn since 2000.
GM Europe has 12 factories, two in Britain. Just under 4,500 people work in Ellesmere Port and Luton.
Vauxhall built 192,000 cars and vans here last year - most were exported, mostly to the single market which we are in the process of leaving. And there's the rub.
Last week GM Europe revealed that would have made money in 2016 had Britain not voted to leave the EU.
The plunge in the value of the pound since the referendum cost the company more than £200 million and has left the Vauxhall operation vulnerable again.
Devaluation should help British manufacturers but two weeks ago the former head of GM Europe, Nick Reilly, Vauxhall's particular vulnerability is that while the 5-door Astrais is built at Ellesmere Port only 25% of the car is sourced in Britain - the rest of the parts are imported. The company is almost certainly losing money as a result.