**Subject: File Number 4-913 — Comment on Preparations for 24-Hour Trading** To the Securities and Exchange Commission: Persistence Analytics Group LLC / United Grid respectfully submits this comment regarding the Commission’s September 17, 2026 roundtable on preparations for 24-hour trading in the U.S. equity markets. I spent thirteen years on the floor of the New York Stock Exchange, from 1998 through 2011. That experience taught me that market resilience depends not merely on whether trading systems remain operational, but on whether liquidity, surveillance, clearing, human accountability, and recovery mechanisms continue to function when conditions become stressed. Extending trading toward a continuous 24-hour model is not simply an expansion of access. It is a material redesign of the operating assumptions beneath U.S. equity-market structure. Before broader implementation, the Commission should require evidence addressing the following questions: 1. **Liquidity and price discovery:** What minimum liquidity, quoting, and market-maker participation will exist overnight? How will investors be protected when spreads widen, displayed depth disappears, or a small number of participants dominate price formation? 2. **Correlated withdrawal risk:** What happens when multiple market makers, broker-dealers, or automated systems activate risk controls simultaneously? The Commission should evaluate whether safeguards designed to protect individual firms could collectively create market-wide liquidity failure. 3. **Clearing, settlement, and margin:** How will continuous trading interact with clearing cycles, collateral calls, settlement processing, corporate actions, securities lending, and overnight funding markets that do not operate continuously? 4. **Surveillance and enforcement:** Will exchanges, FINRA, the SEC, clearing agencies, and broker-dealers maintain equivalent surveillance and response capacity throughout all hours? Continuous trading should not create lower-supervision periods in which manipulation, spoofing, cross-market abuse, or improper order handling becomes harder to detect. 5. **Cybersecurity and operational resilience:** When will exchanges, brokers, market-data providers, clearing systems, and vendors perform maintenance, upgrades, testing, and recovery exercises? A system that never closes requires a verified operating model for patching, failover, incident containment, and controlled service interruption. 6. **Corporate disclosure:** How will material corporate announcements be timed when the market is always open? Issuers and investors need clear rules governing disclosure windows, trading halts, earnings releases, and the equal distribution of material information. 7. **Retail-investor protection:** Will retail investors receive materially inferior execution during thin overnight sessions? The Commission should require transparent disclosures regarding spreads, depth, volatility, execution quality, routing, and liquidity differences by trading period. 8. **Human oversight and accountability:** Which decisions remain subject to qualified human review during overnight hours? Faster and more continuous automation should not reduce accountability when systems behave unexpectedly. 9. **Cross-venue fragmentation:** How will national best bid and offer protections, market-data integrity, order routing, and reopening procedures function if some venues trade continuously while others do not? 10. **Failure and reentry standards:** What conditions trigger coordinated pauses, market-wide halts, or restricted reopening? Reentry after a disruption should be modeled and tested so that simultaneous automated activity does not create a second event. The Commission should require a written, independently reviewable readiness record before approving material expansion. That record should identify each operating assumption, responsible party, supporting evidence, failure threshold, recovery process, and downside owner. Persistence Analytics Group / United Grid recommends a phased approach: * limited overnight pilots with defined instruments and participation thresholds; * mandatory publication of execution-quality and liquidity data by trading period; * coordinated stress testing across exchanges, clearing agencies, broker-dealers, market makers, and critical vendors; * independent verification of cyber, surveillance, staffing, disclosure, and recovery readiness; and * explicit proceed, condition, revise, pause, or terminate criteria before each expansion phase. The Commission should not measure readiness by whether technology can accept orders continuously. The relevant question is whether the entire market structure can preserve fair access, reliable price discovery, investor protection, and orderly recovery continuously. **A market that never closes must also never enter an unverified operating condition.** Respectfully submitted, Neil P. Osnato Founder Persistence Analytics Group LLC | United Grid National Security & Infrastructure Risk Analytics Demand Durability | Grid Stress | Load Integrity [neil@persistenceanalyticsgroup.com](mailto:neil@persistenceanalyticsgroup.com) 609-464-9055 https : / / persistenceanalyticsgroup . com SAM . gov Registered Vendor UEI: D3VYU39H6DX9 | CAGE: 19T34 D-U-N-S: 142849930