HM Revenue and Customs (HMRC) has confirmed it is consulting on whether to tax fund rebates paid to customers.
Currently rebates from platforms to consumers made in either unit or cash form are not subject to any additional taxation.
However, HMRC has told Investment Week, IFAonline's sister title, it is considering amending the rules.
It said in a statement: "The tax status of regular payments by platforms to investors under current legislation has been raised with HMRC and we are considering whether the correct tax treatment is being applied by the platforms and the recipients of such payments."
The confirmation comes after Investment Week revealed the Revenue was looking into making the changes earlier this week.
A tax on rebates would hit bundled share classes, which are offered by most of the UK's platforms, and would impact both unit rebates and rebates to clients' cash accounts.
HMRC is preparing to take action in order to close off what it sees as a potential way for consumers to avoid paying tax.
It is the latest assault on rebates, following the Financial Services Authority's (FSA) announcement last year that it intends to ban payments from providers to platforms and cash rebates to consumers.
In its most recent consultation paper, the regulator said the way in which the consumer currently pays for the platform service "hinders transparency" and "has the potential to negatively affect competition in the market".
Final rules will be published this quarter.
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