Profits at the Steam Packet Company fell sharply last year, according to documents to be considered by Tynwald next month.
The group's annual directors report and financial statement is due to be laid before the court when it sits in December.
They show operating profits fell by £3.7 million to £8 million.
The company says the number of passengers on its ferries was at its highest level since 2007, but its costs had risen and there'd been a below-inflation fare increase.