Group 300 chief executive Chris Batten says the firm could bring a case against the FSA over its treatment of collapsed IFA network Network 300.
Network 300 was placed into administration when the FSA removed its authorisation, blaming insufficient resources.
Batten says the FSA would not allow £1.2m spent on developing new technology to be counted as an asset, affecting the network's solvency and forcing it into administration.
The FSA says N300 dec-lined to take voluntary action to cease conducting regulated activities despite requests from the regulator, leaving it with no alternative but to remove authorisation.
Batten says this is completely inaccurate and says the deal with Thinc for N300's client base and assets was done before the FSA took any action.
Batten says: “We have European and US attorneys working on this and I believe we will have a case against the FSA very shortly.”
The FSA says a firm in this situation has the opportunity to take its case to a tribunal.