Legal & General Group has responded to reports the UK regulator is set to release details of an investigation into the policies of insurance firms to determine whether they treated customers fairly.The Financial Conduct Authority is expected to announce next week that it will check 30m insurance policies worth 150bn pounds over concerns clients were exploited, the UK's Telegraph reported.The news sent insurance stocks sliding including Legal & General and Aviva on the FTSE 100.L&G released a statement on Friday, urging the FCA to bring forward the publication of the plan "in view of today's disorderly market"."We have a strong and substantive commitment to treating our customers fairly and offering low-charging, good value products," the company added."Our operating practices ensure we provide good value to our customers, and we have operated a programme of ongoing product reviews for more than 10 years." The regulator will reportedly look at pensions, endowments, investment bonds and life insurance policies sold in the UK between the 1970s and 2000. The review will begin this summer, the paper said.The FCA is understood to be concerned about insurers using so-called "zombie" funds to pay bills from other parts of their businesses.Legal & General said it "looks forward with confidence" to working with the FCA once it issues official guidance about the potential review due to its "high standards in governance".Shares slumped 7.53% to 196.40p at 13:54 on Friday.RD