Only two of the 28 defendants tried last year were acquitted; those found guilty received prison sentences ranging from six months to 10 years. In 1991, all 17 of those tried were convicted and sentenced to up to six years.
Jeremy Orme, the SIB's director of enforcement, said the statistics had a message for fraudsters: 'You will be found out and you will go to jail. Detection rates are rising and this, rather than an absolute increase in fraud, seems to be behind the growth in cases.'
Mr Orme warned investors to be on their guard: 'Most of the cases involve 'special funds', where deceipt and misappropriation later turn out to be the only special features. If a deal offered by an investment adviser appears to be too good to miss, it probably is too dangerous to take.'
Regulators uncovered 40 cases of investment fraud last year, an increase from 32 in 1991. This takes to 145 the total of cases detected since the current system of investor protection was introduced in 1988. Subsequent criminal investigations have led to 68 convictions.
Most of the frauds arise among life insurance advisers, the problems dividing almost equally between company-controlled firms of tied agents and independent financial advisers. The SIB is seriously concerned about poor standards in the life insurance market and wants to see improvements from Fimbra and Lautro, the junior regulators, and their proposed successor, the Personal Investment Authority.
Peter Clowes, the former head of the Barlow Clowes investment empire, was among those convicted last year, and he received the heaviest sentence. Two of his co-defendants were cleared of the charges against them.
Another high-profile case was that of Bob Kissane, a Royal Life salesman, who received a two- and-a-half-year sentence.
According to the SIB's figures, 11 cases are awaiting trial, while another 72 are still under investigation - including one dating back to 1988. Over the years, eight cases have been closed without charges being brought; on three occasions this was because of the death of the person under investigation.