The three UK-based firms want the Financial Ombudsman to wait until after the verdict on the case with the FSCS has been delivered before paying the victims compensation totalling £362,000.
In a hearing held in October, Thirlwall said a large number of investors in Keydata products had “suffered significant losses”.
The failings were related to flawed sales of Keydata life settlement products. The advice given to clients was said to “demonstrate a complete disregard for [the client’s] individual circumstances and interests”.
Since 2011 the FSCS has paid out more than £300m in compensation to clients invested in Keydata products.
A decision will be made on the appeal application by 17 March.
The financial advisers are due to appear for trial at the High Court early this year.