The following is an update to our April 2026 article, The End of the Closing Bell: Rethinking Institutional Trading in a 23/5 Cycle.
For decades, the structure of global capital markets has been tied to a predictable rhythm. Exchanges opened, liquidity concentrated within regional sessions, and markets closed at the end of each day. This cadence has shaped the investment industry’s entire operating model.
The SEC has now moved the 23/5 conversation from exchange-by-exchange proposals into an industry-wide readiness discussion. SEC Chair Paul Atkins stated that the agency will examine whether U.S. equity markets can support trading 23 hours a day, five days a week, with a one-hour daily pause for systems maintenance and software updates. The SEC plans to hold a public roundtable on September 17 to discuss infrastructure, liquidity, investor protections, and operational readiness for round-the-clock stock market operations.
Exchanges Push Toward 24-Hour Markets
In late 2025, Nasdaq and Cboe Global Markets made headlines by announcing plans in extend trading hours, while the NYSE ARCA received SEC approval to lengthen its trading day from 16 hours to 22 hours, adding an overnight session with a two-hour nightly shutdown to process corporate actions and ensure the market remains orderly.
Then in July 2026, the London Stock Exchange Group announced plans to launch LSE 24, a 24/5 venue for near-continuous trading from Monday to Friday. Client testing is expected by year-end 2026, with exchange-traded products launching in the first half of 2027, subject to regulatory approval.
For decades, global markets ran on a predictable daily rhythm that shaped investment operating models. Regional trading windows gave even global firms natural pauses to process, reconcile, and reset. But that rhythm is changing, and operating models must now change with it.
The SEC Has Entered the Chat
The regulatory focus has now broadened from individual exchange proposals to a more formal SEC-led assessment of market-wide readiness for 23/5 trading. That shift moves the debate beyond demand for extended access and places infrastructure, liquidity, investor protection, surveillance, and operational resilience at the center of the discussion. The planned September 17 roundtable creates a clearer forum for industry input and may shape both the path and pace of future approvals.
Post-trade readiness will remain a gating factor. Clearing, settlement, corporate actions, reference data, and end-of-day processing all need to evolve before near-continuous equity trading can operate at scale.
For institutional investors, the implications are becoming more urgent: asset managers should begin assessing staffing models, risk controls, data architecture, and books-of-record processes for a market structure with fewer natural pauses.
The Elimination of the Daily Reset
Investment operations, accounting, data management, and technology architectures have historically depended on the existence of a daily market close. As that boundary erodes, firms must rethink how positions are maintained, books of record are defined, and control frameworks operate when there is no longer a clean end-of-day reset.
There are several areas that need to be considered:
- Implications for Investment Operations ─ The move to continuous markets requires a corresponding evolution in operating models. Investment operations organizations must transition from batch-processing mindsets to event-driven workflows. Instead of developing solutions to mitigate daily cycles, teams must monitor processes continuously and intervene when exceptions arise. Traders will need greater awareness of corporate actions impacting trade execution, and EMS/OMS integration with corporate action systems will become even more important.
- Data and Technology Architecture Considerations ─ Continuous markets place significant demands on data infrastructure. Firms must move toward unified data models that represent transactions, positions, and reference data consistently across the enterprise. Streaming and event-driven architectures become critical, and cloud-native platforms provide the elasticity needed to handle variable processing loads across time zones.
- NAV Production, Client Reporting, and Regulatory Implications ─ Net asset value (NAV) calculations and client reporting processes are deeply tied to valuation cut-off times. Continuous trading makes determining the appropriate valuation point more complex and increases demand for intraday transparency. Firms must establish governance policies that define when positions are considered official for reporting purposes.
Preparing for a Market That Never Really Closes
The move toward 23/5 trading represents a structural shift in market infrastructure, and the SEC’s September roundtable signals that the industry is entering a more formal readiness phase. As trading becomes nearly continuous, traditional batch cycles and separate books of record become harder to sustain.
AI is likely to play a larger supervisory role over existing execution algorithms in the future. Potential use cases include monitoring overnight news, adjusting execution tactics such as liquidity shifts, coordinating collateral movements, selecting execution venues, and escalating exceptions when predefined risk thresholds are breached.
Rule builders are already common across the market, helping firms automate bespoke workflows, while smart order routing directs trading based on market signals and other advanced criteria. Next-generation rule builders are now incorporating agentic AI, using prompts to generate new rules, and the challenge will shift from building better trading algorithms to governing autonomous execution within clearly defined investment mandates. Over time, more firms will leverage AI for trade execution and auto-routing will move from static rules to more adaptive models.
For many asset managers, extended trading hours will create cost, staffing, and technology challenges they are not yet structured to absorb. Firms will need to look beyond tactical fixes and consider new operating models that can control both cost and complexity.
How Can We Help?
Cutter Associates serves the operational and technology needs of the global asset and wealth management industry. We have helped some of the largest investment management firms around the world achieve business value from every process, realize strategic opportunities, keep pace with the competition, and stay ahead of the technology curve.
The movement toward a 23/5 trading environment represents a structural change to a long-standing rhythm. Investment managers will need to rethink institutional trading and the processes that support it. If you are interested in exploring the best path forward, let’s talk. To learn more or speak with a member of the Cutter Consulting team, contact us at [email protected].