If they slumped, however, the investors would be able to claim tax relief on their worthless shares.

A man who tricked more than 1,000 people out of 70 million by selling worthless shares was told to repay 10.8 million to his victims.

Boiler rooms are typically unregulated overseas operations that target investors using high-pressure sales tactics to sell usually overpriced or worthless shares.

Fraud could be generating a profit of 14 billion a year and hitting at some of the weakest and most vulnerable in society with worthless shares and dubious prize draws.

They allowed the employees to swap their worthless shares for more that had a higher value.