The acquisition by Swiss Re's business unit Admin Re from private equity company Cinven will boost the group's presence in Britain, Swiss Re said in a statement.
“This acquisition is an excellent opportunity for Admin Re to further enlarge its successful business and diversify its portfolio,” said CEO Michel Lies.
“It is proof that we can deliver on our ambitions to seek profitable growth opportunities for Admin Re in the UK.”
Both Admin Re and Guardian are buyers and consolidators of blocks of in-force life and pension insurance policies.
The acquisition will give Admin Re an additional 900,000 annuity, life insurance and pension policies in Britain and Ireland, Swiss Re said.
Admin Re said the additional policies would bring economies of scale and the company aimed to provide the same quality of service as it does to its current 3.4 million customers.
Company executives said the purchase fit within the Swiss Re Group's strategic goals and multi-year financial planning, and would not jeopardize a share buy-back programme.
Admin Re said cash on its balance sheet as well as debt financing would be used to purchase Guardian.
The deal, subject to regulatory approval, is expected to be finalized early next year.