Market Structure Overview

Quick Answer

New securities sell in the primary market; later trades occur in the secondary market. The NYSE uses an auction model, while dealer markets use competing market-maker quotes. Over-the-counter (OTC) means off-exchange execution, which can use dealer quotes or electronic matching. Listing status, venue, and participants distinguish the four secondary market categories.

The distinction matters because venue and pricing mechanism answer different questions. An exchange or an off-exchange electronic network can match orders; a dealer can quote prices and trade from inventory.


How Do Primary and Secondary Markets Differ?

  • 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.


What Are 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 exchangeNYSE, 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 through alternative trading systems, with no broker-dealer intermediaryECNs, dark 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.


How Does an Auction Market Differ From a Dealer Market?

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

FeatureAuction MarketDealer Market
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)

OTC describes off-exchange execution, not one pricing mechanism. Dealer trades and off-exchange electronic order matching can both be OTC.

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).

What Should You Check on Exam Day?

  • Can you place a described trade into the right one of the four markets (first through fourth)?
  • Do you know the third market is exchange-listed securities trading OTC, not unlisted securities?
  • Can you distinguish auction matching from dealer quotations, and explain why OTC execution can use either dealer trading or electronic matching?