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 government has postponed the start date of incoming tax regime FATCA to give businesses more time to comply with the rules.
Offshore tax havens Guernsey, Jersey and the Isle of Man are working towards an agreement with the US government on FATCA, the incoming regime to prevent tax evasion.
A rule change in complex new US tax legislation could see IFAs faced with a bill of up to £100 per client, according to PwC.
The Association of Investment Companies (AIC) has suggested to members with modest investments in US securities that they may be better off not signing up to controversial tax initiative FATCA and taking the penalty charge.
The European Fund and Asset Management Association (EFAMA) is calling on the US government to extend its intergovernmental approach beyond the five countries listed in a recent joint statement.