Ports and ferries group P&O has received a £3.5bn takeover approach from Singaporean state-owned operator PSA International.
P&O is the world's fourth largest ports operator
In a statement P&O said the approach valued its shares at 470p, beating the takeover offer of 443p a share it has already agreed with Dubai Ports.
It said it would give PSA until early February to examine its accounts and decide whether to make a formal bid.
Ports are benefiting from expanding Asian exports to the US and Europe.
World trade volumes are expected to grow 7.6% in 2006, according to the International Monetary Fund (IMF).
PSA is wholly owned by Temasek, the Singapore government investment agency, which already owns 4.1% of P&O.
Founded in 1837, P&O has three divisions - ferries, ports and logistics.
In its heyday in the mid-1920s, it owned a fleet of almost 500 ships before transforming itself in the post-war era to concentrate more on cargo shipping and ports.