The National Securities Depository Limited (NSDL) Services Limited and Central Depository Services Limited (CDSL) are Central Depository of securities in electronic format. In simple, all the equity stocks, debt instrument and other financial instrument that comes under regulated market either comes under NSDL or CDSL.

NSDL is promoted by NSE while CDSL is promoted by BSE. Institutions like banks, stock broking firm registered under any of them act as agents on behalf of the NSDL and CDSL. So they are known as Depository Participants. Everyone who wish to buy or sell shares or any financial instrument is required to have account with the DP, that is your broker or the bank, to keep the shares. When you open your DP account, you have the choice to opt for NSDL or CDSL.