Mutual fund schemes face prescribed base expense ratio limits, defined permitted expenses, and AUM-linked fee ceilings. Regulation 66 mandates that mutual fund scheme expenses be identified and paid from the scheme within prescribed base expense ratio limits, with any excess borne by the AMC, trustees or sponsors after reversal of investment/advisory fees. It enumerates permissible recurring expenses, requires disclosure of investment/advisory fees, prescribes maximum base expense ratio ceilings by scheme type and AUM slabs, allows limited additional brokerage outside the base limit, and treats transaction costs and statutory levies as excluded from the base expense ratio.