First Group has signalled it is considering breaking itself up by seeking a buyer for its Greyhound buses operations in the US.
The Aberdeen-based company, under fire from an activist investor, is also looking at the sale of its UK buses arm, First Bus.
Matthew Gregory, chief executive since November, provided the update as the group reported its annual results.
The group’s losses were £97.9m, narrower than £327m a year earlier.
The company, which owns Great Western Railway (GWR), is facing pressure from one of its investors to boost returns to shareholders in the business, which also operates the distinctive yellow school buses in the US.
The company also signalled that the First Rail business – which also operates the South Western Railway and TransPennine Express – was also under review, depending on future government strategy.
That rail division has generated £331m for the group over the last five years but the group now has “concerns with the current balance of risk and reward being offered”.
The value of South Western Railway, which runs trains out of London’s Waterloo, is being written down by £100m.
Mr Gregory told BBC Radio 4’s Today Programme this was a “problematic franchise”.
Coast Capital Management, which owns almost 10% of First Group, wants to remove six of its 11 board directors and install seven of its own.
Mr Gregory said: “Since becoming chief executive in November 2018, I have been focused on setting the group on a clear path to enhance value.”