A consortium led by investment bank Goldman Sachs has raised its takeover offer for ports operator Associated British Ports (ABP) to £2.8bn ($5.1bn).
Port assets are in demand as global trade flourishes
ABP chiefs have recommended the new 910 pence per share bid, raised from 840p.
The Goldman group decided to raise its offer after Australian bank Macquarie and allies also offered to buy ABP.
Analysts said there may be further bids after Macquarie explained it was considering its position and would make an "announcement in due course".
ABP's shares jumped 36 pence, or 4.1%, to 917p in early trading on Friday.
"The Goldman consortium have demonstrated how extraordinarily keen they are to secure ABP," said Gerald Khoo, an analyst at Oriel Securities.
Mr Khoo said the improved bid could prove to be a "knock out offer".
ABP, owner of 21 UK ports including Southampton, Grimsby and Hull, is the latest ports group to attract bid interest as global trade booms.
THE GOLDMAN-LED GROUP
Borealis Infrastructure Management
GIC Special Investments
In a controversial move in March, Dubai Ports World bought ports and shipping firm P&O for £3.9bn after winning a bidding war with Singapore's PSA International.
The UK's Mersey Docks and PD Ports have also been taken over during the past year.
THE MACQUARIE-LED GROUP
Canada Pension Plan Investment Board
Industry Funds Management
Companies such as ABP offer investors a relatively steady stream of business and earnings, as well as valuable real estate and property holdings.
ABP, which began life as the British Transport Docks Board in 1962, said that the latest offer from the Goldman-led group was "fair and reasonable".
However, the Macquarie-led consortium advised ABP shareholders not to take any action while it reviews its position.
Last week, the Macquarie group offered to match its rival's initial 840p per share bid.
Analysts said that Goldman would be keen to win its battle for ABP after it failed to secure recent bids for airports group BAA, broadcaster ITV and pub company Mitchells & Butlers.
The Goldman-led consortium includes Borealis Infrastructure Management, which is linked to Canadian pension fund OMERS, and GIC Special Investments, a company that is tied to the Singapore government.
Macquarie has lined up allies that include the Canada Pension Plan Investment Board and Australian fund-management firm Industry Funds Management. UK private equity group 3i has withdrawn from the group of bidders.