Alternative Trading System (ATS) vs Stock Exchange: Key Differences
Short answer. A stock exchange is a registered national securities exchange that lists companies, writes rules for its members and supervises them. An alternative trading system (ATS) is a trading venue run by a broker-dealer that matches buyers and sellers under lighter regulation, with no listings and no self-regulatory role. Many dark pools are ATSs.
Side by side
| Alternative trading system (ATS) | Stock exchange | |
|---|---|---|
| Regulatory status | Registered national securities exchange, a self-regulatory organisation | Operated by a registered broker-dealer under Regulation ATS |
| Lists companies | Yes, with listing standards | No, it only trades securities listed elsewhere |
| Rule-making | Writes and enforces rules for members and issuers | Rules apply to its subscribers by contract; no rule-making role |
| Transparency | Public order book and quotes | Often non-displayed (dark) or limited display |
| Typical users | All investors via brokers | Mostly institutions and broker order flow |
| Examples | NYSE, Nasdaq | Dark pools, crossing networks, some electronic communication networks |
| Why it exists | Central price discovery and listing | Lower impact for large orders, extra liquidity, lower fees |
Which one fits you?
Lean towards Alternative trading system (ATS) if…
- you need a listing and a public price-discovery venue
- you want rules enforced by a self-regulatory organisation
Lean towards Stock exchange if…
- you trade large blocks and want to limit market impact
- you want a venue with distinct matching rules or fees
Frequently asked questions
Is a dark pool an ATS?
Most are. A dark pool is an ATS that does not display orders before they trade.
Are ATSs regulated?
Yes. In the US they must register as broker-dealers, file Form ATS with the SEC and follow Regulation ATS, but they are not exchanges.
Can an ATS become an exchange?
Yes. Several venues started as ATSs and later registered as exchanges.
General education, not personal financial advice. Figures are typical US examples and vary by provider and year.