The Investment Management Association (IMA) has written to HM Revenue & Customs (HMRC) to express its concerns over the "continued uncertainty" for companies trying to comply with the Foreign Account Tax Compliance Act (FATCA).
The US law - approved by the US Congress in 2010 - is aimed at catching out tax evasion by US citizens and has the potential to impact a number of advisers and their support partners.
Details have yet to be finalised, but from the start of 2014 all foreign financial institutions that either have US clients or hold US assets in any form will have to be compliant with FATCA.
In its response to an HMRC consultation on the legislation, the IMA said it is concerned not enough information on the impact of the rule change has been provided to UK financial institutions (UKFIs).
"IMA shares the concerns expressed by other industry bodies on the continued uncertainty surrounding the registration process for UKFIs.
"There is now an urgent need to clarify how the registration process will work in practice, and how the UK regulations will mandate all UKFIs to register with the US.
"Until more information is available about the registration process, and how UKFIs can be identified by a FATCA ID number, UKFIs are unable to make meaningful progress in implementing FATCA due diligence."
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