In late 2014, prompted by several high-profile technology-based market disruptions, the SEC adopted Regulation Systems Compliance and Integrity (Regulation SCI), which applies to certain self-regulatory organizations, alternative trading systems (ATSs), plan processors and exempt clearing agencies (collectively, SCI entities). Regulation SCI requires SCI entities to adopt and enforce policies and procedures reasonably designed to protect their technological systems; promptly address systems disruptions; and file periodic reports with the SEC regarding such systems. In September 2026, the SEC imposed a substantial fine on a broker-dealer that operates several ATSs for failing to maintain certain policies and procedures mandated by Regulation SCI and, critically, repeatedly failing to remedy compliance deficiencies noted by SEC staff. This article looks at the key requirements of Regulation SCI, the broker-dealer's alleged compliance failures and the terms of its settlement with the SEC. See “SEC 2025 Exam Priorities Stress Core Fiduciary Duties and Effective Compliance Programs” (Dec. 5, 2024); and “Present and Former SEC Attorneys Discuss Retail Investors, CAT Implementation, Enforcement Issues, Reg BI and SRO Oversight” (Dec. 12, 2019).