Insurer Amlin has been placed under review by rating agency AM Best in the wake of this week’s announced agreement to be acquired by Japan’s Mitsui Sumitomo Insurance Company in a $5.3 billion deal.

Amlin operates in the Lloyd’s of London market and also has an office in Bermuda. Mitsui Sumitomo is a unit of Tokyo-based MS&AD Insurance Group.

AM Best has placed Amlin plc’s issuer credit rating of “a-” under review with developing implications, with a similar under-review status being applied to “a+” issuer credit rating and “A” financial strength rating of Switzerland-based Amlin AG.

The issuer credit rating of Lloyd’s Syndicate 2001 has also been placed under review by AM Best.

The agency said is was evaluating Mitsui Sumitomo Insurance’s plans for Amlin and its subsidiaries, and the impact of the transaction on the risk-adjusted capitalisation of the Amlin entities.

In a statement it said: “AM Best expects to resolve the under review status of the ratings upon completion of the transaction.

“The transaction is subject to the approval of Amlin’s shareholders and regulatory approval, and is expected to close in the first quarter of 2016.”

In a statement regarding the deal, Charles Philipps, Amlin’s chief executive officer, said: “We believe that this combination is extremely compelling.

“We have always had a very high regard for MSI, our strategies and corporate values are closely aligned, and this transaction will now provide Amlin with the increased scale and financial muscle that will be required for long term success in our industry.

“It delivers excellent value for shareholders, improved career prospects for our employees, and enhanced continuity and security for our clients.

“I am confident that, with our combined skills and geographic coverage, we will continue to go from strength to strength.

“We believe that our respective Lloyd’s, Bermudian and European businesses fit well together and will allow increased development opportunities.”

He added: “MSI’s presence in the ASEAN region and its ambitions in the United States clearly offer very exciting prospects for Amlin. We are looking forward to working closely with MSI’s management and the MSI teams with whom we will be combining.”

When contacted by The Royal Gazette, a spokesman for Amlin said it was too early to say whether or not the acquisition would have an impact on Amlin’s operations in Bermuda.