The shares fell as much as 11.5% at one stage.
Go-Ahead was named this summer as the preferred bidder to operate about 10% of the bus routes in Dublin.
Passenger growth is slowing at the UK’s Southeastern network, which operates trains into five major terminals including London Bridge and Victoria station, Go-Ahead said in a statement. The firm will also suffer a revenue slump after losing the London Midland contract, while it is locked in talks over a move to driver-only trains that led to strikes.
“Southeastern depends on what is happening in central London,” said Go-Ahead chief executive David Brown. “If there are doubts about the economy, people are reluctant to spend money on a season ticket for travel months ahead.”
Mr Brown said Go-Ahead had also seen some impact on discretionary travel at London Bridge, where three terrorist attackers swerved a van into pedestrians on June 3 before going on a stabbing spree in nearby bars, killing seven people.
Go-Ahead said it is engaged in a “constructive dialogue” with the Aslef train-drivers’ union over plans for doors to be closed from the cab rather than by guards on services operated by its Southern business, which connects the counties of Kent and Sussex with London Bridge and Victoria stations. Aslef members have already rejected a deal backed by officials. Mr Brown said there’s less engagement with the RMT labour group, whose members have staged a series of strikes over the new working practices.
Pretax profit fell 5.7% to £136.8m (€150m) in the year-ended July 1, Go-Ahead reported, with bus earnings flat and rail suffering a 16% decline.
Go-Ahead shares have fallen 25% since the start of the year.
Additional reporting Irish Examiner