New EU disclosure rules, Mifid II (Markets in Financial Instruments Directive II) - effective from 3 January - were designed to offer greater protection for investors and inject more transparency into all asset classes. The directive requires investment managers to disclose all additional transaction costs that are charged to their funds, on top of the established ongoing charging fund figure. According to Lang Cat, a pension and investment consultancy, the size of the hidden costs that investors have been paying (as revealed under Mifid II) was a "real eye opener". Across the top 20 selling funds of 2016, investors in 13 funds paid on average 30 per cent, and as much as 85 per cent, more in additional transaction fees than had previously been disclosed to them.