Would-be merger partners Axis and PartnerRe said they would sweeten the deal for shareholders in a bid to stave off a hostile bid by Italian investment giants Exor.

And the two Bermuda companies said on Friday that meetings of shareholders in the two firms to vote on the deal would be delayed by two weeks as a result.

A statement issued jointly by the two firms said: “PartnerRe and Axis Capital are committed to ensuring that common and preferred shareholders benefit materially from the combination of the two companies.

“The companies will communicate enhancements to their amalgamation agreement in the near-term.”

But the statement added that “there can be no assurance that the companies will reach agreement on any enhancements to the terms of their amalgamation agreement”.

Both companies have recommended that their shareholders back the $11 billion, all-share merger over Exor’s $6.8 billion cash bid for PartnerRe.

But a spokesman for Exor said: “By postponing its own shareholder meeting, PartnerRe continues its attempts to rescue an inferior transaction that is the result of a flawed process.

“Exor remains committed to bringing its offer to fruition for the benefit of all PartnerRe shareholders.”

Exor, which had earlier raised its original $6.4 billion offer for PartnerRe, last week unveiled enhanced terms for both common and preferred shareholders in the target firm.

Preferred shareholders — a crucial voting bloc — were offered a 100 basis point increase in the dividend rate and call protection for five years on all three series of preferred shares, which Exor said would provide preferred shareholders with “certainty of income for a significantly extended period”.

The Italian, firm, controlled by the billionaire Agnelli family, said it would also limit capital distributions to around two-thirds of earnings for five years.

Also among the new terms was a “go shop” provision, which would allow PartnerRe to look for third-party bids up to August 31, even after signing a deal with Exor.

Exor also said that during the period allowed for PartnerRe to look for another buyer, it would reduce the termination fee to $135 million.

The PartnerRe and Axis termination and expense reimbursement fee, payable if either side walks away from the deal, was set at $315 million.