Smurfit Kappa said to be under pressure to negotiate with International Paper

The Sunday Times cited one investor as saying: "If International Paper makes an offer of more than €40 a share then Smurfit Kappa should start talking to the Americans."

In late March, Smurfit rejected a second offer from Memphis-based International Paper valuing the shares at €37.54, up from €36.46.

Smurfit said at the time that the revised proposal "fundamentally" undervalued the group and was still significantly below the valuations set by recent industry transactions.

Smurfit chairman Liam O'Mahony said: "The revised proposal does not offer Smurfit Kappa shareholders much more than compensation for the fall in International Paper’s share price since that date and again entirely fails to value the group’s true intrinsic business worth and future prospects. We delivered a record performance in 2017 and underlying trading momentum has continued into 2018.

"Moreover, the revised proposal does not make strategic sense for Smurfit Kappa and its stakeholders. Smurfit Kappa has a distinct business model and culture as a customer-oriented, performance-led packaging leader and has already communicated a strong plan to accelerate development and performance with its 2017 year-end results."

At 0935 BST, the shares were up 1.8% to 3,034.50p.