JLT and HSBC are set to join Smart & Cook and Giles Insurance in selling a new captive product, backed by City financier Sir Mark Weinberg.
Synergy MicroCaptive, launched this week, is aimed at medium-sized companies, spending less than £1m on insurance cover.
It adapts the captive concept used by larger corporations.
Unlike conventional insurance, 30 to 40% of the annual net premium is allocated to an interest bearing account, in the client's name, to cover smaller losses.
The remainder pays for insurance cover on larger claims but if a business manages its risks well it gets the money in the account back.
Sebastian James chief executive of the company behind the launch, Synergy Insurance Services, said it was in talks with JLT and HSBC to distribute the product.
Synergy was also in discussions with eight other brokers, some of which were regional brokers.
Smart & Cook and Giles have already agreed to sell the product.
Weinberg, founder of Allied Dunbar Assurance and co-founder of St James's Place Wealth Management is chairman of Synergy.
Inter Hannover, part of reinsurer Hannover Re will underwrite the product.