The High Court of England and Wales has barred The Prudential Assurance Company (PAC) from transferring $15bn annuities to Rothesay Life.

If the transaction has not been blocked, it would have been the largest ever such transfer.

The transaction, originally signed in March last year, was supposed to cover approximately 400,000 policy holders.

Prudential said in a statement: “We are disappointed by the High Court’s decision. The Independent Expert, who was appointed to report to the High Court, concluded the transfer would have no material adverse effect on the security of benefits or the reasonable benefit expectations of our policyholders.

“PAC and Rothesay Life have been granted leave to appeal the judgment by the High Court.”

Insurance companies are selling closed books of annuity operations to shore up the capital buffer after the European Union introduced strict capital rules.

Prudential further said that the High Court’s decision would have no impact on the company’s planned demerger of its insurance and asset management business in UK.

The demerger is scheduled to be completed during the fourth quarter.