Therefore the FCA wants to see providers resolving complaints as quickly as possible.
Data from the FCA showed there is now £184bn in assets under administration across the Sipp operator market, compared to around £130bn in 2022.
There has also been an increase in assets under administration on platform-based Sipps.
The FCA said that in total, assets under administration within Sipps reported by all firms now stands at £567bn for 5.3mn consumers.
Non-standard assets within all Sipps now account for around 1.57 per cent of the total assets under administration (compared to 2 per cent in 2022).
Most new non-standard assets have been in more secure asset types, such as unbreakable fixed term deposits and NS&I products.
amy.austin@ft.com