Hartley Pensions has been prevented from taking on new business since 4 March.

An asset sale restriction has also been put in place.

The FCA restriction did not disclose the reasons for the change.

The regulator said Hartley Pensions must also contact its five largest SIPP and SSAS business partners to let them know they cannot accept further SIPP or SASS business from them.

Hartley Pensions provides pension administration services and white-labelled SIPPs used by a number of third parties, including platforms and Financial Planners.

Adviser platform Hubwise has partnered with Hartley Pensions for its white-labelled Hubwise Hartley SIPP proposition since 2019.

The platform may now have to use a different SIPP administrator for new clients.

Hartley Pensions can still receive new contributions from existing clients who already hold a SIPP or SSAS operated by the firm but may not generate a pipeline of clients or accept any new clients.

The restriction applies to all new clients, other than pipeline SIPP/SSAS business clients. Clients it can continue to take on include any SIPP or SSAS business being processed, including where a switch or transfer of funds has been requested by a client but not yet completed.

The firm is also able to take on new clients where expressly authorised in writing by the FCA.

A spokesperson from Hartley Pensions said the restriction was voluntary.

The spokesperson said: “There is no impact on existing Hartley clients and we are in contact with all advisers and other business partners so their clients are informed.

“We are committed to delivering the highest standards of products and services for our customers and are working closely to address feedback from the regulator before taking on additional SIPP or SSAS clients. This has been a voluntary action by Hartley and we are working closely with the FCA to address feedback.”

Hartley Pensions has taken on the client books from several failed SIPP providers in recent years. It bought the Guinness Mahon client book in February 2020 after the firm collapsed. The deal meant the transfer of 4,000 SIPPs previously administered by GMTC which suffered a string of problems and legal actions from unhappy clients.

Other SIPP books the firm has purchased in recent years include GPC, Berkeley Burke SIPP and Greyfriars AM.

Hartley Pensions, Hubwise and the FCA have been approached for comment.

• This is a developing story, please check back for updates.