Description

BSE modifies member level throttle limit/MPS subscription from monthly to weekly cycle and introduces monthly billing based on peak MPS allocation in equity derivatives segment.

Summary

BSE has modified the Trading Member level Throttle Limit/Messages Per Second (MPS) framework in the Equity Derivatives segment. The key changes include transition from monthly to weekly subscription cycle for MPS limit revision requests, and introduction of monthly billing based on peak MPS allocation during the calendar month.

Key Points

  • MPS subscription cycle changed from monthly to weekly effective November 6, 2025
  • Trading Members can submit MPS revision requests every Thursday (or previous trading day if Thursday/Friday is a holiday)
  • Revised MPS limits become effective from T+2 trading day (following Monday)
  • Monthly billing will be based on peak MPS limit during the calendar month
  • For work weeks spanning two calendar months, peak MPS from overlapping week applies to both months
  • First weekly submission window opens Thursday, November 6, 2025 for limits applicable from November 10, 2025
  • All other existing terms and conditions of MPS limit policy remain unchanged

Regulatory Changes

This circular modifies the existing member level throttle limit/MPS framework established under Exchange notice 20250527-65 dated May 27, 2025. The primary regulatory changes are:

  1. Subscription Frequency: Weekly revision requests replace monthly requests
  2. Billing Methodology: Introduction of peak-based monthly billing instead of fixed monthly charges
  3. Cross-month Treatment: Special billing provisions for work weeks spanning two calendar months

Compliance Requirements

For Trading Members:

  • Submit member level MPS revision requests through UCC portal every Thursday
  • If Thursday and/or Friday is a trading holiday, submit requests on the previous trading day
  • Plan MPS requirements with understanding that revised limits take effect from T+2 trading day (following Monday)
  • Monitor peak MPS usage as it determines monthly billing charges
  • Note that peak MPS during weeks spanning two calendar months will be charged in both months

Timeline for Implementation:

  • First submission window: Thursday, November 6, 2025
  • First effective date for revised limits: Monday, November 10, 2025

Important Dates

  • October 28, 2025: Circular issued
  • November 6, 2025: First Thursday when Trading Members can submit weekly MPS revision requests
  • November 10, 2025: Revised MPS limits from first weekly cycle become effective
  • Weekly thereafter: Every Thursday becomes submission day for MPS revision requests

Impact Assessment

Operational Impact:

  • Trading Members gain increased flexibility with weekly revision capability instead of monthly
  • Faster response time (T+2) allows members to adjust to changing trading volumes more dynamically
  • Members need to establish weekly monitoring and request submission processes

Financial Impact:

  • Billing methodology change to peak-based monthly charges may increase costs for members with variable MPS requirements
  • Members experiencing peak usage during cross-month weeks face billing impact in both months
  • Potential cost optimization opportunity for members who can manage peak usage within single calendar months

Risk Management:

  • Weekly revision capability allows better alignment of MPS limits with actual trading needs
  • Reduced risk of throttling during high-volume periods due to more frequent adjustment windows
  • Members must balance operational flexibility against potential cost implications of peak-based billing

Impact Justification

Procedural change affecting trading member operations with modified subscription cycle and billing methodology, requires operational adjustments but not immediately critical