Mock Trading for Closing Auction Session Testing · NSE/FAOP/74791

National Stock Exchange of India Limited

Circular

All Members,

Mock trading on Saturday, June 20, 2026 – Testing of Trading modalities related to Introduction of Closing Auction Session (CAS) in Equity Cash segment

With reference to circular no. NSE/FAOP/74467 dated May 29, 2026 regarding ‘Introduction of Closing Auction Session (CAS) in the Equity Cash segment - Change in trading modalities in the Equity Derivatives segment’, Exchange shall be conducting a mock trading session in the Futures & Options segment on Saturday, June 20, 2026.

Further, Exchange shall be introducing new NEATPlus version (7.8.9) for aforesaid CAS implementation related testing. Members must note that said new NEATPlus version shall be applicable only during the Trading Session-1 of the mock. Post Trading session 1, members shall have to reinstall and login with earlier NEATPlus version (7.8.8) for Trading Session-2 & 3 which shall be conducted as per existing Trading modalities without changes related to CAS. Kindly refer point A, B and C for more information.

*Random closure in last one minute
#Trades from trading session 1 shall not be available in trading session 2 & 3. However, Trades from trading session 2 shall be available in trading session 3. Members are requested to actively participate in all trading sessions.

Members are required to take note of the below important points:

A) Below NEATPlus version should be used explicitly for mock session 1 only:

B) During the trading session 1, in order to align the price band for stock future contacts applicable during the CAS in CM segment, the reference price shall be determined based on the VWAP of the trades executed in the respective stock futures between 10:10 a.m. and 10:25 a.m.

C) For trading session 2 & 3 and Live trading from June 22, 2026, kindly use below NEATPlus version :

➢ NEATPlus version (7.8.8 & 7.8.9) are compatible with new broadcast parameters. For information regarding market data parameters, kindly refer the circular NSE/MSD/74448 dated May 27, 2026.

D) New CA Certificate
➢ Members are requested to refer to circular no. NSE/MSD/74511 dated June 02, 2026 regarding new CA certificate and NSE/MSD/74559 dated June 05, 2026 for new version of Neat Adapter EXE application. Accordingly, members are requested to use the combination of new NEAT adapter version and new ports applicable for F&O derivatives segment as below:

Members using Direct connection through NNF users, are requested to download and use the new CA certificate which is available in Extranet path ( /faoftp/faocommon/Encryption_CA_Certificate/2026_Certificate). Accordingly, members shall ensure readiness of their migration plan by July 06, 2026. The applicable new interactive parameters to be used with ‘New CA certificate’:

*Port – This port will support new encryption messages with MD5 checksum removal.
**Port - This port will support new encryption messages with MD5 checksum removal and new immediate Ack request for order related messages.

For other important instructions regarding the mock trading, kindly refer to the following Annexure:
Annexure 1: Important instructions regarding mock trading session.
Annexure 2: Pre-requisites / General guidelines for participating in the Mock environment.
Annexure 3: Important guidelines in case of switchover of trading system to Disaster Recovery (DR) Site.

For and on behalf of
National Stock Exchange of India Limited

Aarti Surve
Chief Manager

Annexure – 1

Important instructions regarding mock trading session