UK ports and ferries operator P&O has received approaches on a potential takeover, its board said on Sunday.
P&O has recently been scaling down its activities
"P&O confirms that it has received a preliminary contact... which may or may not lead to an offer," the firm said.
The Sunday Times says the interested party is Dubai Ports World, owned by the United Arab Emirates government, which could bid £3bn ($5.35bn).
It said Dubai Ports has hired Deutsche Bank to advise it on a bid, and a first meeting with P&O could take place soon.
The Gulf firm manages ports in Asia, Europe, Australia and South America, and P&O owns ports around the world.
Last week P&O, which has been slimming down its ferries and property arms, cut back earnings expectations for its key ports business.
In the past year there has been strong growth at its Asian ports, but that has been offset by more sluggish economic conditions in the UK and Australia.
Any developments will be watched closely by others in the market, such as Singaporean state investment firm Temasek and Danish shipping group A.
In August P&O, full name Peninsular & Oriental Steam Navigation, unveiled a sharp dip in first-half earnings. Pre-tax profits were £30.6m, down from £53.4m at the same time in 2004.
P&O has been selling properties and slashing jobs at its loss-making ferry operations as part of a shake-up.
The company was forced to rethink its strategy as budget airlines and the Channel Tunnel eroded its market share.
Over 1,000 job losses were announced in 2004 and P&O has since cut back on routes.
The final P&O voyage from Portsmouth to Le Havre set sail at the end of September, with the loss of 350 jobs.
P&O had also been conducting a property disposal programme - in June, the company offloaded its 25% stake in Dutch shipping company P&O Nedlloyd, leading to a £187.9m one-off gain.