Cobra - the network that launched earlier this year - said that it now has 20 members with a total premium income of £100m per year.
The Surrey-based network said this was double the initial target. Cobra, which was launched in June, said it aimed to attract commercial brokers with a premium income of between £1m and £6m.
Cobra's panel of insurers includes Allianz Cornhill, AXA, NIG, Norwich Union and Zurich.
Managing director John Lincoln said he hoped to expand Cobra to 100 brokers by this time next year.