E2M says advisers are responsible for the majority share of mortgage transactions (58%) and carried out more than 6.8 million residential mortgage sales between 2003 and 2007.
But it claims an estimated 60% of advisers fail to recommend conveyancing services to clients.
With the average fee for conveyancing standing at £100 per referral, advisers could have lost up to £330m during this period or an average of £1,600 per intermediary each month.
This is based on an average of 16 mortgage transactions per month per adviser.
E2M says the £1,600 fee is worth more than two average mortgage proc fees.
Karen Babington, marketing director at E2M, says: “I’m not surprised to see that advisers have missed out on such a large amount of commission – advisers seem to fall into two groups – the ones that have tried using a conveyancing company and realised the income benefits and the other group who don’t refer at all.”
She adds: “I would suggest that advisers who don’t currently earn income from conveyancing should research a number of providers and pick the one that they gain the most confidence from.
“They can then commit to recommending this service every time they do a mortgage appointment and watch their revenue streams improve.”