The findings by adviser technology firm Intelliflo also show that just one quarter of advisers have already contacted clients to advise on the removal of the commission, which provides them with an annual fee over the lifetime of a product they have sold.
Another third plan to contact clients before the end of 2015.
For a third of investors, the trail commission represents less than 10% of income, while one in five said it currently accounts for a third or more of their income.
A quarter said they do not plan to contact all clients until the end of March 2016.
Nick Eatock, executive chairman at Intelliflo, said: “The findings of our survey highlight the challenges faced by advisers as the full range of RDR related changes come into force.
“With the clock ticking and such significant levels of income still coming from trail commission, there is an urgent need for advisers to communicate with clients and move them to a fully fee-based model.”
The UK’s Financial Conduct Authority first banned trail commission in April 2014 as part of the implementation of legislation following the Retail Distribution Review (RDR), which banned the receipt of commission in favour of a fee-based remuneration model.
However, it allowed advisers a two year grace period lasting until April 2016, known as the “sunset clause”, to make the transition away from trail commission.
Last month, a report by Garry Heath, the former director general of the association of IFAs, predicted that between 7,260 and 15,510 advisers will be affected by the removal.
Heath predicted that the ban could at worst lead to a 47% loss in adviser capacity when added to the 13,500 advisers he predicts to have already been displaced by the RDR.