The City regulator has imposed a record £2.8m fine on a stockbroker who ran a "rotten" scheme to ramp up the price of shares he owned.
The Financial Services Authority (FSA) said Simon Eagle showed "breathtaking disregard" for the effect his actions had on his clients and the markets.
Mr Eagle has to pay back £1.5m in profit he made and a fine of £1.3m - the largest against an individual.
Mr Eagle has also been banned from working in finance.
The FSA said he was responsible for a "complex and prolonged abusive scheme" that set out to artificially inflate the share price of Fundamental-E Investments (FEI).
Mr Eagle had bought 85% of the company, which was listed on the AIM exchange.
He then bought a stockbroking firm, installing himself as chief executive, and used it to generate demand for the stock, pushing up its price.
Some of the demand was bogus, the regulator said, with staff at the firm trading stock on behalf of clients who did not know the shares were being bought and soldin their names.
As a result of that artificial increase in demand, the FEI's share price increased from 2.5 pence in May 2003 to 11.75p in July 2004.
As well as benefiting from an increase in the value of the shares, Simon Eagle also received £1.2m in commission on the sale of FEI shares.
"This scheme was rotten throughout and at the core was Simon Eagle," the FSA said.
"He involved others in his activities and exposed individual clients to serious financial debts of over £9m.
"His conduct breached the LSE's [London Stock Exchange's] rules, caused significant disruption to share dealing in FEI shares, and damaged confidence in the AIM market."