According to the prosecution in the case, the losses Mr Bunn made led to 12 employees losing their jobs and the remaining staff receiving a 20 per cent pay cut.
He adopted a short position to nearly seven million HSBC shares, then lied to LCS over the trades by using forged share purchase slips.
The court heard that as the HSBC share price increased, his gamble âspiralled out of controlâ which led to LSC making the loss.
Judge Geoffrey Rivlin, the Honorary Recorder of Westminster, said: "You were not stealing your company's money but you were gambling with it in a very reckless and dishonest manner.
âI think I can fairly say that as a result of your very serious misconduct you have certainly made a very significant contribution to bringing this company, at least temporarily, to its knees."
Mr Bunn pleaded guilty to four counts of false accounting in May.
He also received a ban from working in the industry from the Financial Services Authority.
By Jim Ottewill