The dent in its books was caused by a September 2023 RBI communique spelling out how banks should value derivatives. It said all derivatives must be marked to market (MTM), which requires valuing assets and liabilities according to prevailing market price. The dent in its books was caused by a September 2023 RBI communique spelling out how banks should value derivatives. It said all derivatives must be marked to market (MTM), which requires valuing assets and liabilities according to prevailing market price. Economic Times