The following Letter Type A, or variations thereof, was submitted by individuals or entities.

Letter Type A:

Re: Comment on the Comprehensive Review of the Consolidated Audit Trail (CAT)
Dear Chairman Atkins and Commissioners,

I respectfully urge the Commission to preserve the Consolidated Audit Trail (CAT) in its essential form. The SEC’s concept release of April 2026 raises legitimate questions about cost and governance. However, the appropriate response to those concerns is targeted reform, NOT the elimination of the only surveillance infrastructure capable of protecting ordinary investors in modern US equity markets.

I. The CAT is the Minimum Viable Infrastructure for Investor Protection
Before the CAT existed, major market disruptions took years to investigate because order data was siloed across dozens of exchanges and brokers. Sophisticated bad actors exploited these gaps deliberately. Activity was spread across venues precisely because no single regulator could reconstruct a complete picture. The 2010 Flash Crash took five years to partially explain. Congress and the Commission recognised this failure and mandated a solution through Rule 613 in 2012.
Markets are faster, more complex, and more fragmented today than they were in 2012. The case for unified surveillance has grown stronger, not weaker. Reverting to pre-CAT infrastructure will re-create an environment in which large-scale manipulation is feasible and largely undetectable, or traceable.

II. Three Dangers That Follow Closure

1. Market manipulation becomes undetectable.

Spoofing, layering, and coordinated price manipulation leave no visible trace to the retail investor watching a screen. They are only detectable when regulators can reconstruct the precise sequence of orders across every participant simultaneously. Without CAT, the SEC must revert to fragmented records, a system that sophisticated already actors know how to exploit. The retail investor, who has no access to order flow data at all, bears the cost of this information asymmetry.

2. Best execution obligations become unenforceable.

Every retail investor has a legal right to have their order routed to the best available price. CAT is the primary mechanism through which regulators can verify whether brokers are honouring that obligation or routing orders to venues that pay them more. Without it, payment-for-order-flow abuses and execution quality failures become moot, the evidence simply will not exist.

3. Removal of Deterrence

The most important effect of comprehensive surveillance is the activity it prevents rather than the activity it catches. Institutions that know every order is permanently recorded and traceable to a specific account make different decisions than those operating without oversight. Closing the CAT signals to every sophisticated market participant that they may manipulate markets with impunity. The integrity benefits of CAT are largely invisible precisely because they exist.

III. The Arguments for Closure Do Not Withstand Scrutiny

The Commission’s concept release identifies three areas of concern: cost, cybersecurity, and whether existing audit trails are sufficient. Each is legitimate. None justifies closure.

Cost: The SEC has already identified $50–$70 million in annual savings through operational reform. The cost per trade protected is a fraction of a cent against the billions in annual retail investor losses attributable to manipulation. The answer to cost concerns is continued optimisation, not elimination of the infrastructure.

Cybersecurity: A centralised data system does create a target and that risk deserves serious investment in security architecture. But every major financial system, from SWIFT to the Federal Reserve, holds sensitive data and protects it. The privacy risk of a breach is real. The privacy risk of undetectable manipulation without CAT is certain, it is simply less visible.

Adequacy of existing trails: Pre-CAT audit trails were exchange-specific and could not follow an order’s lifecycle across venues, link related accounts, or reconstruct cross-market activity. Modern manipulation specifically exploits the gaps between fragmented systems. CAT was built to close those gaps. No combination of pre-existing tools replicates that capability.

IV. Reform, Not Removal

The Commission has already demonstrated that meaningful cost reduction is achievable without compromising the CAT’s core surveillance function. The path forward is continued reform on cost, governance, and security. NOT a retreat from the principle that regulators require complete, unified order data to protect investors.

If the CAT is closed or structurally hollowed out, the beneficiaries will not be retail investors. They will be the sophisticated actors whose advantage grows when oversight contracts. Markets function when participants trust them, that trust is maintained through enforceable rules and demonstrable accountability. The CAT is not a regulatory luxury. It is the minimum infrastructure required for the Commission to fulfil its legal mandate.

I respectfully urge the Commission to maintain the CAT, reform its costs and governance where warranted, and reject any proposal that would leave investors without the protections that unified market surveillance provides.