Six men have been convicted of offences relating to insider dealing which netted them £732,000 in profits.
Ali Mustafa, Pardip Saini, Paresh Shah, Neten Shah, Bijal Shah, and Truptesh Patel were all found guilty following a four and a half month trial at Southwark Crown Court.
They had obtained confidential and price-sensitive information from investment banks concerning proposed or forthcoming takeover bids, which they then used to place spread bets.
Among the company stocks they dealt with were Reuters, Biffa and Premier Oil and, trading between 1 May 2006 and 31 May 2008, they made a combined profit of £732,044.59.
With hundreds of trading accounts and telephone records examined, the Financial Services Authority (FSA) described it as the "longest and most complex prosecution" it has brought so far.
One other defendent, Mitesh Shah, was acquitted of insider dealing.
Tracey McDermott, acting director of the FSA's enforcement and financial crime division, said: "Our success in bringing these individuals to justice is the result of innovative and determined work done across our markets, intelligence and enforcement teams over several years.
"This sort of behaviour poses a significant risk to the integrity of markets and cheats honest investors. We will continue to use all of the tools at our disposal to ensure those who seek to abuse the system have nowhere to hide.
"The conduct of the individuals in this case and the details of the scheme which have now been revealed are important reminders to firms of the need to protect inside information throughout its life so that it cannot be misused."
All six will be sentenced on Friday.
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