Description
NSE will conduct mock trading on December 20, 2025, with UCC live environment unavailable from 10 AM to midnight. Members advised to refrain from UCC modifications during this period.
Summary
NSE will conduct mock trading on Saturday, December 20, 2025, as previously announced through multiple circulars. During this mock trading session, the Unique Client Code (UCC) live environment will be unavailable from 10 AM until midnight. Members are advised to refrain from making any UCC modifications or uploads during this period as any changes will be purged and not considered valid for live trading resuming Monday, December 22, 2025.
Key Points
- Mock trading session scheduled for Saturday, December 20, 2025
- UCC live environment will be unavailable from 10 AM to midnight on December 20, 2025
- Any UCC data added or modified during the unavailability period will not be valid for live trading
- Invalid UCC records will be purged from the Exchange system by end of day December 20, 2025
- Members must avoid all UCC modifications/uploads during the specified timeframe
- This circular supplements earlier circulars: NSE/CMTR/71914, NSE/FAOP/71907, NSE/CD/71910, NSE/SLBS/71909, NSE/DS/71898, and NSE/COM/71911
Regulatory Changes
No permanent regulatory changes. This is a temporary operational adjustment for mock trading purposes.
Compliance Requirements
- Members must refrain from making any UCC modifications or uploads between 10 AM and midnight on Saturday, December 20, 2025
- Members should plan UCC updates before 10 AM on December 20 or after the system becomes available post-midnight
- Any critical UCC changes needed for Monday trading must be completed outside the blackout period
Important Dates
- December 19, 2025: Circular issuance date
- December 20, 2025: Mock trading session day
- December 20, 2025, 10 AM to midnight: UCC live environment unavailable
- December 20, 2025, end of day: Invalid UCC records purged from system
- December 22, 2025 onwards: Live trading resumes (Monday)
Impact Assessment
Operational Impact: Medium - Members cannot perform UCC operations during the 14-hour window, requiring advance planning for client onboarding or modifications. However, the impact is limited as it occurs on a Saturday when regular trading is closed.
Market Impact: Low - No direct market impact as this occurs during a non-trading day. The mock trading session is for testing purposes and does not affect live markets.
Member Action Required: Members need to coordinate their UCC management activities around the blackout period. Any urgent client additions or modifications must be completed before 10 AM on December 20 or deferred until after midnight. The advance notice of one day provides adequate time for planning.
Risk Mitigation: Clear communication ensures members are aware that UCC changes during the blackout will be purged, preventing confusion about missing or invalid client codes when live trading resumes on Monday.
Impact Justification
Medium importance as it affects UCC data management during mock trading session. Members must avoid UCC modifications to prevent data loss, but impact limited to one day with clear advance notice.