The UK's biggest ports operator, AB Ports, has received an improved bid approach from a consortium including Goldman Sachs worth £2.44bn ($4.6bn).
Ports companies are proving popular bid targets
AB said it had received a proposal of 810 pence per share from the consortium and had decided to open its books to the group for a limited period.
In March, AB Ports rejected a bid from the consortium of 730 pence per share, branding the offer "wholly inadequate".
AB Ports runs 21 UK sites and employs more than 3,000 people worldwide.
The company said that there was no certainty over whether an offer would be made or the terms of any possible deal.
Shares in AB Ports closed up 100 pence to 700p.
UK port firms have proved attractive bid targets in recent months, with rising world trade volumes and property assets attracting a range of suitors.
Last year, Mersey Docks and PD Ports were taken over, while earlier this year, Dubai Ports World bought P&O for $6.8bn.
AB Ports handles about a quarter of the UK's seaborne traffic, with sites at locations including Hull, Grimsby, Immingham, Port Talbot and Southampton.
The company also owns AMPORTS in the US, which handles vehicle imports and exports.