The M6 Toll road has been put for sale for nearly £2bn, the BBC understands.
The 27-mile route between Cannock and Coleshill in the West Midlands opened in 2003 and cost £900m to build.
A debt restructuring process led to a consortium of 27 banks effectively taking ownership of the loss-making road from Midlands Expressway Ltd and they are selling their equity stake.
Despite the toll road losing money each year, it is thought the banks want to recover about £1.9bn from the sale.
The Toll, originally called the Birmingham Northern Relief Road, starts at junction 3a of the M6 in Warwickshire and rejoins the motorway at junction 11a in Staffordshire.
In September, a plan to make it free was revealed in a draft proposal for the West Midlands Combined Authority.
Latest figures show 52,735 vehicles used the road per day between October and December last year, compared with 45,890 in 2014.
Car drivers are charged £5.50 to use the road during the week and HGVs £11.
Analysis: BBC Midlands Today Transport Correspondent Peter Plisner
A few years ago there was a restructuring of the debt that was originally financing the building of the road. That restructuring meant 27 different banks effectively took ownership of the road and they’ve now decided to sell their equity stake in the road, which we’re told is worth about £2bn.
The reason they’re selling now is quite interesting.
They seem to think now that the asset value is at its highest – that’s obviously the road and the 50-year concession, a decade of which is already gone.
And the other interesting fact is that the number of people using the road is at an all-time high and that brings in revenue. The interest payments on the debts are lower than they’ve ever been and that will affect this road’s profitability.
It’s always lost money – £25m on average a year. But we’re going to see a difference when we see the next accounts because of all these changes. And that leads the 27 banks to decide to sell now.