The FSA has deployed the services of Big Four accountancy firm Deloitte to quiz platforms about its proposed ban on fund manager and cash rebates.
In its August policy paper, the regulator set out its intention to ban both forms of rebates but delayed a final decision pending further research.
As part of that research, the regulator has hired consultancy firm Deloitte to gauge the views of platform operators.
The revelation has raised further concerns over the cost of the FSA's ongoing research into platform remuneration.
It is understood Deloitte staff have recently had meetings with senior management from major platforms to ask for their views on its proposed rebate ban.
"It was slightly odd it was people from Deloitte that were working on the FSA's behalf," said one insider.
"I can only imagine the regulator have a resources constraint - if you have got to get the work done soon and you haven't got the resources in-house then I guess you have got to get someone from outside to do it. And I imagine it was quite expensive for the FSA."
The FSA declined to comment on the cost of the research, saying the details are commercially sensitive.
Last week it emerged the regulator is examining how platforms are regulated in other countries as part of its study into platform charging models - prompting one IFA to hit out at the "enormous expense" of the exercise.
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