ZIM’s board of directors was forced yesterday to issue a public statement reaffirming that its merger agreement with Hapag-Lloyd and Israeli private equity fund FIMI is legally binding, after an unexpected rival bid from Israeli businessman Haim Sakal sent the shipping company’s share price surging 9.5% on Wall Street.

Sakal submitted an offer of $4.5bn in cash – $300m above the Hapag-Lloyd and FIMI deal – valuing ZIM shares at $37.50 each, a 7.1% premium to the agreed price. The proposal, contained in a letter to ZIM chairman Yair Seroussi, also includes a $250m bonus pool for employees and a pledge to keep ZIM’s fleet of 145 vessels and operational headquarters under full Israeli sovereignty.

ZIM’s response was unambiguous. “ZIM’s board of directors has signed a binding agreement to merge ZIM with the Hapag-Lloyd shipping company, and the agreement was approved by a majority of 97% of the shareholders last week. The deal is binding on the company,” the company said.

Legal experts note the board has no discretion to consider alternative offers at this stage. While the merger agreement technically contains a superior offer provision that would trigger a $150m break fee, that escape route closed upon last week’s shareholder approval. The board can only revisit other proposals if the Hapag-Lloyd deal fails to complete on time and the agreement lapses.

Sakal’s group is also reported to have submitted a separate offer for Israeli airline Arkia.