Bernard Panton, former chairman of Gresham Telecomputing, has applied to the courts for a judicial review of SFA rulings on the sale of his 29.9 per cent stake in his company to Ferrari Holdings, one of Singer's clients, which has since collapsed. Mr Panton, who now lives in Australia, claims that Singer breached SFA rules in its advice to Ferrari shareholders.
Ferrari paid pounds 1.2m for Mr Panton's shares but did not declare this in a document issued a few days later to support a pounds 4.4m rights issue.
Singer says the shares were bought by one of its subsidiaries, which only later sold them to Ferrari. The rights issue was underwritten by Singer, which ended up with a 37 per cent stake in Ferrari.
The SFA twice investigated Singer's involvement in the share purchase. The original investigation, which also exonerated Singer, was reopened after complaints by Mr Panton.
The SFA ruled last December that while there had been a breach of SFA guidelines, the Stock Exchange believed there was insufficient evidence to show Ferrari put had out a false or misleading circular.