The Office of Fair Trading (OFT) has not yet completed its inquiry into dual pricing in the insurance market.
It launched the probe last May, following complaints from a handful of brokers alleging that some insurers were pricing products offered to brokers at higher rates than for direct customers.
Norwich Union was the only insurer to be named by the competition watchdog as being under investigation.
A spokeswoman for the OFT said it was seeking further information from insurance companies and had not yet decided whether its rules on fair competition had been breached.
