Rowanmoor Personal Pensions Limited (RPPL), a self-invested personal pension (SIPP) operator, has gone into administration leaving clients in an uncertain position.

The Financial Conduct Authority (FCA) confirmed the move on 31 August and said the directors had appointed Adam Stephens and Chris Allen of Evelyn Partners LLP as joint administrators.

Rowanmoor operates approximately 4,800 pensions, with assets under administration of £1.4bn.

The FCA explained: "RPPL received complaints about historic high-risk non-standard assets and for not carrying out adequate due diligence before accepting these assets into customers' SIPPs.

"RPPL sought professional advice about the liabilities arising from existing and potential complaints. Having done so, RPPL's directors determined that the company was insolvent and should be placed into administration."

A notice on the FCA website said the administrators would write to clients of RPPL shortly to tell them what to do next.

Although RPPL is in administration, it remains an FCA-authorised firm and is still subject to FCA rules and can continue to operate existing pensions whilst the administrators look for a new operator.

The administrators will also continue to accept regular and ad hoc contributions from clients into their pensions.

Pension assets are held by Rowanmoor Trustees Limited (RTL), which has not entered administration, the FCA notice said. It also added that the Rowanmoor group's small self-administered schemes (SSAS) are not affected as they are operated by Rowanmoor Executive Pensions Limited (REPL), which has not entered administration.

The FCA said that it was looking to all options including the transfer of RPPL's clients to another FCA- regulated SIPP operator, which would likely result in the least disruption to clients.

If unavailable, the administrators will look to pursue other options aimed at transferring SIPPs or returning pension assets back to clients, according to the FCA.

In a FAQ document to clients, the administrators said: "We are in discussions with a potential purchaser and we hope to proceed quickly, with the intention of completing a sale within a short timeframe.

"It is anticipated that any such sale will involve the transfer of responsibility to operate and managed SIPPs and Family Pension Trusts (FPTs) with the commensurate transfer of assets held within the SIPPs and FPTs to the new provider.

"The administrators are pursuing this strategy as part of the objective of maximising realisations for creditors."

The Financial Ombudsman Service (FOS) has upheld three cases against the firm, which are available to view on its website.

In July 2021, platform business Embark and its subsidiary brands -  excluding the £5bn of assets in Rowanmoor -  were sold to Lloyds Banking Group for £390m. The Rowanmoor business was then retained by existing shareholders.