During a seven-day trial, the court heard that Michael Crow had controlled "virtually every significant aspect" of New York-based Duncan Capital, taking the "vast majority" of the company's profits.
However, the firm's regulatory filings did not identify Mr Crow as one of its officers, directors or control affiliates.
Duncan Capital's owner and "nominal president", Robert David Fuchs, was found guilty of making false regulatory reports and transferring part of the company's profits to entities controlled by Mr Crow.
The court ordered Mr Crow and Duncan Capital to pay $1.9 million illegally gained profits and prejudgment interest, Mr Fuchs to return Â£282,874.95 and Mr Crow, Mr Fuchs, Duncan Capital and the Duncan Capital Group to disgorge a total of $4.9 million in ill-gotten gains.
Furthermore, Mr Crow and Mr Fuchs must pay individual fines of $250,000 and $125,000 respectively. Duncan Capital and the Duncan Capital Group must each pay a $50,000 fine.