Exchange Fee Models, Dark Pools & New Venues

The maker-taker model is a fee structure used by most U.S. equity exchanges in which market makers (liquidity providers) receive a rebate for posting limit orders that rest in the book, while market takers (liquidity removers) pay a fee for executing against that resting liquidity.

The model creates financial incentives to provide liquidity, which theoretically improves market quality by narrowing spreads. Critics argue that it creates conflicts of interest for broker-dealers routing orders to maximize rebates rather than execution quality - a concern that has driven multiple SEC and Congressional reviews.

Inverted models reverse the incentive: takers receive a rebate and makers pay a fee. These venues attract order flow that would otherwise sweep away liquidity (aggressive institutional flow), since they pay for taking. No-rebate models (like IEX) charge a single flat take fee and offer no maker rebate, removing the routing conflict entirely.

The NMS Plan amendment under Rule 605 (effective August 1, 2026) will expand execution quality disclosure requirements, making venue-level routing decisions more transparent.

An Alternative Trading System (ATS) is an SEC-registered trading platform that matches buyers and sellers but is not registered as a national securities exchange. Most ATS operate as dark pools, meaning they do not display pre-trade quotes publicly to the consolidated tape.

Dark pools serve a legitimate purpose: allowing large institutional investors to trade large blocks of stock without moving the market against themselves. When a mutual fund needs to sell 5 million shares, displaying that order publicly would cause other participants to front-run the execution, increasing market impact costs.

FINRA Rule 4552 requires ATS to report their weekly trading volume data, which FINRA makes public on a two-week lag. This transparency initiative, launched in 2014, allows the public to see which dark pools are most active, though pre-trade information remains private by design.

Total dark pool and ATS volume has historically represented 35-40% of U.S. NMS equity volume, with the remainder executing on lit exchanges like NYSE, Nasdaq, and Cboe.

The SEC approval of 24X National Exchange and growing overnight equities activity (via Blue Ocean ATS and similar platforms) has significant implications for market data infrastructure:

Feed infrastructure currently assumes scheduled trading hours with maintenance windows overnight. Continuous 23-hour operation would require always-on multicast feeds, eliminating the overnight maintenance window that many market data teams rely on for system updates and connectivity testing.

Consolidated tape (SIP) architecture would need to handle continuous consolidated quote and trade reporting, adding operational complexity. The CTA and UTP Plans have not yet published formal implementation guidance for extended-hours SIP reporting.

Market data engineers should begin evaluating whether their downstream systems (risk engines, data warehouses, analytics platforms) can handle continuous intraday data with no defined daily session boundaries.