The Financial Services Compensation Scheme has reported receiving more than 500 claims relating to Sipps.
Smaller Sipp firms will be best placed to meet the challenges ahead in the sector over the coming year, the managing director of Liberty Sipp believes.
Read more: 'Smaller Sipps firms best are placed to adapt to changes'
The Sipp market will ultimately split into two, one of the leading sipp providers has predicted, while another believes platform Sipps will take the majority of business in future.
Changes to pension rules have provided members of older schemes with a "rare window of opportunity" to transfer to a new pension arrangement and retain any higher tax-free lump sum, a Sipps firm believes.
Read more: Sipps firm: Rare window of opportunity for pension transfer
More than six out of ten complaints about Sipps to the Financial Ombudsman Service have been upheld since 2013.