Several people connected with Tudor Capital Management, a pension scheme administration service provider, have been arrested on suspicion of fraud, cheating the public revenue and money laundering.
Company directors Peter Bradley, Andrew Meeson and Alison Bradley have been involved in the investigation.
Bradley and Meeson are trustees of at least one pension scheme held by Tudor.
Meeson, who is also vice president of the Association of Tax Technicians, was arrested on 7 September, a Wolverhampton Police spokesperson says.
Peter and Alison Bradley, fellow directors of the company, were arrested on 29 April this year.
All were taken to King's Heath Police Station in Birmingham following their arrests.
HMRC was unable to confirm if an investigation is ongoing or if the people named had been bailed or acquitted, although a spokesman could confirm they have not been charged.
A TPR spokesperson says the regulator is unable to comment on individual cases, but adds: "TPR does have power to prohibit or suspend trustees, but this does not happen often; that would be a last resort, as we would rather work with trustees to resolve issues first."
Christine Hallet, chief executive of financial service provider Carey Pensions, confirmed it plans to receive a transfer of a pension trusteeship from Tudor Capital Management.
Tudor Capital Management declined to comment on the issue.
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