Market Structure Overview

Before diving into who makes markets and how, you need the big picture of where securities trade and how the U.S. market is organized.


Primary vs. Secondary Markets

  • The primary market is where new securities are sold to investors for the first time (initial public offerings, new issues)
  • The secondary market is where previously issued securities trade between investors
  • Market makers and exchanges operate in the secondary market, providing liquidity for outstanding securities

Think of it this way: The primary market is the "factory" where securities are created, and the secondary market is the "used market" where they change hands afterward.


The Four Secondary Markets

The secondary market is subdivided into four categories based on where and how trades occur:

MarketDescriptionExamples
First marketTrading on a national securities exchange (auction market)NYSE, Nasdaq
Second marketOver-the-counter (OTC) trading of securities not listed on an exchangeOTC Markets (OTCQX, OTCQB, Pink)
Third marketOTC trading of exchange-listed securitiesInstitutional investors trading NYSE-listed stocks OTC through broker-dealers
Fourth marketDirect institution-to-institution trading via electronic communications networks (ECNs), no intermediaryDark pools, crossing networks
  • The third market allows institutional investors to trade exchange-listed securities OTC, bypassing exchange fees and gaining anonymity for large block trades
  • The fourth market uses Electronic Communications Networks (ECNs) to match buy and sell orders directly between institutional participants

Exam Tip: Gotchas

The third market is specifically about exchange-LISTED securities trading in the OTC market. If a question describes an NYSE-listed stock trading through a broker-dealer off the exchange, that is the third market. A common mix-up is confusing the third market (exchange-listed stocks traded OTC) with the second market (unlisted stocks traded OTC). The key difference is whether the security is listed on an exchange.


Auction Market vs. Dealer Market

These are the two fundamental models for how prices are determined:

FeatureAuction Market (Exchange)Dealer Market (OTC)
Price discoveryCompetitive bidding between buyers and sellersDealers quote bid and ask prices; trades occur at dealer quotes
IntermediaryDesignated Market Maker (DMM) on NYSE maintains orderly marketMultiple competing market makers quote prices
ExamplesNYSE, NYSE AmericanNasdaq, OTC Markets
ExecutionOrders matched through auction processCustomer trades against dealer inventory (principal) or dealer routes to another market (agent)

Exam Tip: Gotchas

Nasdaq is classified as a dealer market, even though it is a national securities exchange. Multiple competing market makers post quotes on Nasdaq, unlike the NYSE where a single DMM is assigned to each security. The exam may ask which market uses an auction process (NYSE) vs. competing dealers (Nasdaq).