The Wesleyan Assurance Society defied the sector trend by driving sales of with-profits bonds up by 76 per cent in 2007, figures from the Birmingham mutual showed yesterday .
It also achieved a 25 per cent increase in new annualised premiums on a net basis.
The figures underlined the success the 167-year-old organisation has had in maintaining its with-profits book as those of its bigger competitors have dwindled.
The Wesleyan, which has assets of about £4 billion, is regularly rated Britain's strongest mutual in financial terms by the independent Cazalet organisation.
Its refusal to get sucked into the boom in internet, telecoms and media stocks in the late 1990s meant it was able to maintain a high level of investment (more than 70 per cent) in equities in the three-year bear market following the millennium and its with-profits fund has since reaped the benefit of the overall recovery.
It specialises in supplying tailored financial products to doctors, dentists, teachers and lawyers.
Chief executive Craig Errington said yesterday that 2007 had been a year of "steady and successful growth" for Wesleyan.
"As the general economic outlook remains uncertain, people will want to think carefully about where to invest their cash," he said. "Wesleyan's with-profits bonds were very successful last year and remain an attractive option for the cautious investor.
"A look at the performance tables shows that our with-profits investments offer some of the best returns in the industry."
Wesleyan is ranked first out of 39 providers of one-year bonds, third out of 33 in the three-year market and third out of 27 over five years.
"Wesleyan's financial strength under-pins our success in the with-profits market. Also, as a mutual we are able to pass on any profits directly to our customers as there are no shareholders to consider," Mr Errington added.