Equity Market Structure
The U.S. equity markets are the most robust in the world – deep, competitive, liquid, efficient, and transparent. They are also among the most highly regulated, playing a vital role in capital formation and investor confidence.
SIFMA advocates for policies that maintain the efficiency and resiliency of U.S. markets while encouraging innovation, fair competition, and cost-effective trading for investors. As regulators evaluate potential reforms, it is critical that any changes be grounded in data, supported by rigorous cost-benefit analysis, and designed to enhance market integrity and investor outcomes.
Market Structure Conference
On November 17–18, 2026, SIFMA will bring together market leaders, innovators, and regulators to examine the regulatory, technology, and trading developments shaping the future of equities and options market structure.
By the Numbers
SIFMA Research
SIFMA Insights
- Equity Market Metrics & Trends
- Equity Market Structure Compendium
- The ABCs of Equity Market Structure
Key Focus Areas
Promoting Market Efficiency and Investor Benefit
Equity market structure drives liquidity, execution quality, and trading costs for investors. Market makers, exchanges, and trading platforms work together to deliver best execution and narrow spreads, benefiting both retail and institutional investors. SIFMA supports market innovations that strengthen efficiency while maintaining competition and transparency.
Supporting Data-Driven Regulatory Reform
As the SEC considers major changes to equity market structure, SIFMA urges a measured approach informed by data and analysis. In 2024, several key regulatory developments reshaped the landscape:
- Rule 605 Modernization (March 2024): Updated disclosure requirements for order execution.
- Regulation NMS Amendments (September 2024): Introduced new quoting increments, lower access fee caps, and enhanced transparency on transaction fees and odd-lot orders.
- Litigation and Stay (October–December 2024): Certain amendments to Rules 610 (access fees) and 612 (tick sizes) were stayed pending judicial review.
SIFMA has long called for a review of equity market structure, having previously presented recommendations designed to enhance the current structure to the SEC and Congress in 2013, 2014 and 2017. We continue to engage with the SEC and market participants to assess implementation and promote a balanced regulatory framework.
Evaluating Extended Trading Hours
With global participation increasing, U.S. exchanges are exploring expanded trading hours. SIFMA supports dialogue on operational readiness and investor impact. Our key recommendations include:
- Unified trading day ending at 8:00 p.m. ET;
- Exchange operations Sunday 9:00 p.m. to Friday 8:00 p.m. ET;
- Opt-in flexibility for firms;
- Infrastructure updates to address settlement, risk management, and corporate actions.
Fostering Market Resilience Through Collaboration
SIFMA works closely with exchanges, market participants, and regulators to ensure market structure evolves responsibly. Our annual Market Structure Conference and ongoing roundtables provide a forum for constructive dialogue on modernization, transparency, and investor outcomes.
The Bottom Line
U.S. equity markets are a global benchmark for liquidity, innovation, and investor protection. SIFMA is committed to preserving their strength through thoughtful modernization, collaborative policymaking, and continued focus on efficient, resilient market structure that benefits all investors.
