A report by Fidelity and the Cass Business School suggests as many as 43 million Britons could fall into what they call a "guidance gap" as a result of the Retail Distribution Review (RDR).
The gap comprises those people that will be without professional financial advice in the post-RDR world and that will not have the confidence to make their own decisions in the absence of professional advice, but who will be in need of financial guidance in order to maintain the health of their personal finances.
The report estimates the total investible wealth of this group is approximately £440bn.
It also said that it is "very possible" that more people could fall into the guidance gap over time.
"The Financial Services Authority's (FSA) goal may have been to improve the average quality of financial advice, and the RDR may well achieve this aim, but at the same time it seems likely to us that both the demand for and the supply of financial advice are likely to shrink as a consequence of this new regulatory regime," the report's authors said.
They add: "Without a commensurate increase in the supply of high quality guidance, the quality of personal finances in the UK is unlikely to improve."
The report also found just 14% or 7 million UK adults say they are likely to pay a fee for advice.
People demonstrated a strong appetite for alternatives with 50% saying they would use a guidance service instead of advice.
The survey suggests that the average level of investible assets needed to make a consumer commercially viable to an adviser is approximately £61,000.
The report found that around 75% of the UK's adult population did not have current investible assets above this level.
The investors who said they would not pay a fee for financial advice in the future have average investible savings of £43,000.
Only 31% of advisers expected to keep most of their clients, according to the research.
