MEMX Imposes Micro-Fees for Audit Trail Expenses Through 2026
Published Date: 5/15/2026
Notice
Summary
Starting May 1, 2026, MEMX is charging industry members a tiny fee of $0.000001 per share traded to help cover the costs of the Consolidated Audit Trail (CAT) system. This fee will last through the end of 2026 and aims to cover about two-thirds of the CAT’s budgeted expenses. Brokers will get their first bill in June based on May’s trades, so everyone involved should get ready to chip in!
Analyzed Economic Effects
5 provisions identified: 0 benefits, 5 costs, 0 mixed.
Per-Share CAT Fee Set at $0.000001
Beginning May 1, 2026 and running through December 31, 2026, MEMX will assess CAT Fee 2026-1 of $0.000001 per executed equivalent share. The Operating Committee calculated an underlying Fee Rate of $0.000003799483243631228 per executed equivalent share, then divided that rate by three and rounded to arrive at $0.000001 per executed equivalent share.
Brokers Billed Monthly; First Invoice June
CAT Executing Brokers for the Buyer (CEBB) and for the Seller (CEBS) will be billed monthly for CAT Fee 2026-1. CAT Executing Brokers will receive their first monthly invoice in June 2026 based on transactions they executed as CEBB and/or CEBS in May 2026.
Who Bears the $15.15M CAT Budget
The Budgeted CAT Costs for May–December 2026 are $15,149,648. CEBBs collectively are allocated one-third of those costs ($5,049,882.67) and CEBSs collectively are allocated one-third of those costs ($5,049,882.67); Participants are intended to contribute the remaining one-third.
How Shares Are Counted for Fees
For calculating CAT Fees, executed equivalent shares are counted as: each executed share in NMS Stocks = 1 executed equivalent share; each executed Listed Options contract = multiplier (e.g., 100 executed equivalent shares); each executed OTC Equity share = 0.01 executed equivalent share.
Regulator Noted Brokers May Pass-Through Fees
The Commission noted in its approval order that Industry Members may pass-through CAT fees for customer executed volume. That means brokers could charge customers for these CAT fees on executed trades.
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Key Dates
Department and Agencies
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