A discounted fine of £21,000 has been levied agaist Mohammed Suba Miah, a former broker at Square Mile Securities Limited, with the FSA subsequently banning him from conducting regulated business.
After reviewing 19 transactions carried out between December 2005 and May 2006, the regulator found that in 11 of them Miah had been dishonest by recording the purchase of high risk shares by customers without their permission.
This meant that customers would have only been made aware of the trades when they were sent a demand for payment.
Miah also made inaccurate and misleading claims about the performance and value of the shares and failed to inform customers of the higher risks associated with buying them.
His actions were considered particularly serious by the FSA because of the abuse of trust.
"Customers have a right to expect their brokers to give clear and fair advice, recommend suitable shares and to treat them fairly," said Margaret Cole, FSA director of enforcement. "Our actions against Mr Miah show that we take this very seriously."