Two men and three women have been arrested as part of a crackdown by the financial regulator over insider dealing and market abuse.
Raids were carried out at at properties in London, Lincolnshire, Leicestershire and North Yorkshire. Those arrested were aged between 37 and 63.
The FSA has so far secured 21 convictions for insider dealing and has stepped up its efforts to tackle market abuse over the past few years.
The latest arrests are not linked to any other ongoing insider dealing probes.