The proposed merger between Just Retirement and Partnership has been put on hold subject to meeting Solvency II requirements and is expected in January.
In statements issued to the stock exchange, both insurers said they would wait for the Prudential Regulatory Authority to approve their proposed internal model for Solvency II, which is expected in first half of December.
The internal model is one of the mechanisms insurers can apply to ensure they are compliant with Solvency II regulation's on risk and capital requirements.
Shareholder meetings to vote on the proposed merger, which had originally been scheduled for 26 November, will now go ahead on 5 January 2016.
In September Just Retirement and Partnership said they were looking to raise £150m in equity capital to help meet the costs of their planned £1.6bn merger announced in August.
Further reading