Suffolk Life is to acquire around 1,700 plans from rival Pointon York's self-invested personal pension (SIPP) book.
The mutually agreed acquisition comes after Pointon York decided to close the scheme to new business.
David Hobbs, managing director of Suffolk Life, said "Suffolk Life has been committed to the self-invested pension market for over 40 years and we have made no secret of our intention to grow our business both organically and via the right acquisitions. The Pointon York book of business fits well into the bespoke end of our proposition and should add around 1,700 additional SIPPs."
Suffolk Life also said it will use retained profits for the purchase and remains "strongly capitalised" ahead of expected FSA changes to capital requirements for SIPP providers.
Greg Kingston, head of marketing for Suffolk Life said: "This move provides further evidence that consolidation is here, as different operators are making decisions about the future strategy of their businesses.
"Consolidation is positive for the SIPP market, injecting capital and enabling investment and focus in new directions. This specific deal delivers a secure, known, long term future for the SIPPs of all these advisers and their investors."
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