Channel ferry operator Condor has been bought by a consortium made up of Brittany Ferries and an investment fund.
Condor currently operates between Portsmouth, Poole, Guernsey, Jersey and St Malo, and carries about a million passengers every year.
The company was put up for sale in 2018 by its Australian owner the Macquarie Group, which bought it in 2008.
The deal still has to be approved by regulators.
The Columbia Threadneedle European Sustainable Infrastructure Fund said it was "looking forward to working with management, employees and the Channel Islands".
Brittany Ferries, which operates between the UK, France, Spain and Ireland, said it has bought a "minority stake" in the company.
For the Channel Islands, Condor is a lifeline service, providing the only ferry routes to the UK and France.
Jersey's government welcomed the sale, describing the combination of Brittany Ferries and the investment fund as "grounds for optimism in the future development of our ferry services".
Charles Parkinson, president of Guernsey's economic development committee, called the deal "extremely positive news".
"Having had the opportunity to meet with the new investors I am also confident in their commitment to help Condor deliver ongoing improvements to the resilience, reliability and affordability of our passenger and freight services," he added.
Founded in 1964 by Channel Island businessmen Peter Dorey and Jack Norman, Condor operates passenger services between the Channel Islands and France.
The ferry network was expanded in 1987 when the company launched the first route connecting the Channel Islands with the UK.
Condor currently operates with four ships, including the high-speed vessels Rapide and Liberation, all-weather Commodore Clipper and a freight service Commodore Goodwill.
The operator carries more than one million passengers, 200,000 passenger vehicles and 100,000 freight vehicles to the islands each year.
The Condor brand is expected to remain intact, with Heiko Schupp from Columbia Threadneedle describing the ferry operator as an "attractive first investment" due to its market fundamentals, stable financial position and management team.
Travel journalist Simon Calder said the deal means Brittany Ferries would be able to run a more logistically-sensible operation, combining the two companies.
"It also means, frankly, a bit of competition is taken out of the market - it's all about scale in travel, and this will help Condor be part of a bigger enterprise," he added.