RBI vide notification No. RBI/2021-22/81 dated 25th August, 2021 has issued Master Direction for Classification, Valuation and Operation of Investment Portfolio of Commercial Banks (Directions), 2021.
To enable banks to have current instructions at one place, a Master Direction incorporating all the existing guidelines / instructions / directives on the subject has been prepared for reference of the banks.
https://www.rbi.org.in/Scripts/NotificationUs
er.aspx?Id=12153&Mode=0#CHP10