Source: https://databento.com/docs/faqs/venues-and-publishers



# Venues and publishers

You may have seen other data sources refer to all trading venues as an
*exchange*. This naming convention is often harmless, especially if you
are only interested in a small set of venues that actually implement a
centralized exchange model.

However, as you expand to more asset classes or markets with Databento, it
becomes increasingly likely that you will encounter different venue models
such as ECNs and ATSs. Since terms like *exchange*, *ATS*, and *ECN* have
specific regulatory meanings, we refrain from conflating *exchange* with
other trading venues.

We use the terms "**trading venue**" and **venue** interchangeably.

We use the term ***publisher*** to refer to any data provider on Databento.
A publisher may also be a venue.

> **Info**
>
> A vast majority of US equities data consumers are receiving data
> disseminated by the Securities Information Processors (SIPs) --namely
> the Consolidated Tape Association (CTA) and the UTP Plan. The SIPs provide
> a consolidated view of all protected bid/ask quotes and trades from US
> equities trading venues. On Databento, we refer to the SIPs as ***publishers***
> but not market operators.

### Exchange

An **exchange** is a venue registered with the SEC under
[Section 6](https://www.nyse.com/publicdocs/nyse/regulation/nyse/sea34.pdf) of
the Securities Exchange Act of 1934. The SEC lists all current exchanges
registered,
[here](https://www.sec.gov/fast-answers/divisionsmarketregmrexchangesshtml.html).

### OTC markets

**OTC markets** are dealer networks that trade securities that don't meet
exchange listing requirements (such as "unlisted" securities) and instruments
that don't trade on a formal exchange (such as bonds, ADRs, and derivatives).
The Financial Industry Regulatory Authority (FINRA) regulates broker-dealers
that operate in the over-the-counter (OTC) market.

### ATS

An **Alternative Trading System (ATS)** is a non-exchange trading venue that
matches buyers and sellers to counterparties for transactions. ATSs are usually
regulated as broker-dealers instead of as exchanges.

ATSes meet the definition of exchange under federal securities law. They aren't
required to register as a national securities exchange, as long as the ATS
operates under the exemption provided under
[Exchange Act Rule 3a1-1(a)](https://www.law.cornell.edu/cfr/text/17/240.3a1-1).
Since ATSes are non-exchanges, ATS transactions don't appear on national exchange
order books. Some traders use this advantage to conceal trading from public view,
and reduce the effect of large trades.

An ATS must be approved by the United States Securities and Exchange Commission
(SEC). For a current list of SEC-recognized ATSes, see
[here](https://www.sec.gov/foia/docs/atslist.htm). The equivalent term under
European legislation is a ***multilateral trading facility (MTF)***. ATSes are
inclusive of **electronic communications networks (ECNs)**, **cross networks**, **call networks**, and
**dark pools**.

### ECN

**ECNs** are a type of alternative trading
system (ATS) that trade listed stocks and other exchange-traded products
outside of traditional stock exchanges. As an ATS, ECNs are required to register
with the SEC as broker-dealers as well as register as members of FINRA.

ECNs are computerized systems that internally and automatically match limit
orders, charging a fee for each transaction. These venues attempt to eliminate
the third party's role in executing orders entered by an exchange market maker
or an over-the-counter market maker. They permit such orders to be executed
against in whole or in part.

### Dark pools

**Dark pools** are a type of ATS that operate within private groups. They are
private exchanges or forums for securities trading. Though their legal validity
 is subject to local regulations, they are popular for participants who want
  to disassociate their identity from market activity, and for participants
   who want to save money on transaction fees.

| Type | Overview | Examples |
| Exchange | Regulated by the SEC under [ Section 6 ]( https://www.nyse.com/publicdocs/nyse/regulation/nyse/sea34.pdf ) of the Securities Exchange Act of 1934 | Nasdaq, NYSE, Cboe, TYO |
| OTC markets | Regulated by FINRA. Dealer networks that trade unlisted securities and instruments that don't trade on formal exchanges (such as bonds, ADRs, and derivatives). | Best Market (OTCQX), the Venture Market (OTCQB), and the Pink Open Market |
| ATS | Regulated as broker-dealers. Exempt from SEC "exchange" regulation under [ Exchange Act Rule 3a1-1(a) ]( https://www.law.cornell.edu/cfr/text/17/240.3a1-1 ). | BrokerTec, Nasdaq Fixed Income |
| ECN | A type of ATS. A computerized system that automatically matches limit orders. | Pepperstone, FXCM, IC Markets |
| MTF | The European equivalent of an ATS. Regulated under MiFID II. | Chi-X Europe |
| Dark pools | A type of ATS. Operated within private groups as exchanges or forums. Popular for participants who want to disassociate their identity with market activity or save money on transaction fees. | Robinhood, CrossFinder, Sigma X, Citi-Match, MS Pool, Instinet, Liquidnet, ITG Posit, GETCO, Knight |