A group of investors are attempting to bring claims against self-invested personal pension (Sipp) provider Liberty Sipp.
The 27 claimants have instructed Wixted & Co Solicitors to pursue Liberty Sipp over the way the Sipps were set up.
The claimants held investments in their Sipps in the likes of Ethical Forestry, Sustainable AgroEnergy and Gravity Child Care, which had been introduced to them by six unregulated firms.
There will be a case management conference at the Bristol Circuit Commercial Court on 6 June but a spokesman for Wixted said any trial hearing is unlikely to take place until 2019 at the earliest.
John Fox, managing director of Liberty Sipp, said: "Liberty refutes any suggestion that it has ever mis-sold investments, and will defend itself in the strongest terms from such false accusations.
"As a Sipp provider, Liberty cannot offer financial advice or sell investments. So by definition we cannot mis-sell investments."
He said the claims related to a few legacy clients who opened Sipps with Liberty Sipp between 2011 and 2013.
Liberty Sipp stopped allowing clients to invest in non-standard assets in 2013, and today more than 96 per cent of the assets it has under management are in standard, regulated investments.
Timothy Hampson, associate solicitor at Wixted & Co, said: "We are not accusing them of selling investments or advising on them."