The Financial Services Authority (FSA) has created a new set of rules that require all investment firms to record electronic communications to help the FSA fight market abuse.
From March next year, companies making investments for clients will have to retain all electronic data as well as telephone conversations related to the customer's investment for six months.
"We expect this to act as a deterrent or a way to gather information if there is a suspicion of market abuse," said an FSA spokesperson.
After consulting the industry, the original plan to force companies to retain the data for three years was because of fears over excessive costs.
"Following responses from the industry and concerns over costs, we cut the period to six months," said the spokesperson.