What is a market?

What a market actually is

A financial market is, at its core, a mechanism by which buyers and sellers discover prices for instruments — the catch-all word for anything tradeable: stocks, bonds, contracts. Everything else is supporting infrastructure: the exchange (the venue where orders meet), the broker (the firm that carries your orders to the market), the clearinghouse (the middleman that guarantees completed trades), the regulator (the government body setting the rules).

There are two kinds of markets we'll care about:

• Exchange-traded markets. Centralized venues (NYSE, NASDAQ, CME) where buy and sell orders meet in a transparent order book — a live, public list of everyone's outstanding buy and sell orders. Prices are visible to all participants in real time.
• Over-the-counter (OTC) markets. Deals negotiated directly between two parties, with no exchange in the middle. This covers most bonds, most derivatives historically, and all FX (foreign-exchange, i.e. currency) trading. There is no central order book; prices are quoted by dealers — firms that stand ready to buy or sell from their own inventory.

You'll trade exchange-traded equities (stocks) and futures (contracts to buy or sell something at a price fixed today, on a set future date) in this curriculum's exercises. OTC products show up later, when we discuss credit, swaps, and bespoke (custom-built) derivatives — instruments whose value derives from some other asset.

Who's in a market

Every market has roughly four kinds of participants. Recognizing which one you are at any moment matters more than people think.

• Hedgers. People already exposed to a risk, using the market to offset it. Example: a wheat farmer sells wheat futures today to lock in a sale price before harvest.
• Speculators. People with no prior exposure who take a position — a holding, long or short — purely to profit from price movement. Most of what we'll do as quants (traders who rely on math and code) falls here.
• Arbitrageurs. People who exploit price differences between related instruments. Example: the same exposure priced differently as a stock versus a futures contract on it, or a foreign company's US-listed shares (an ADR) versus its home-market shares (the underlying). Their buying and selling helps prices stay consistent across venues.
• Market makers. Firms that continuously quote both a bid — the price at which they'll buy from you — and an ask — the slightly higher price at which they'll sell to you. The gap between the two is the spread, and it's their fee for standing ready. In return they provide liquidity — the ability for everyone else to buy or sell immediately without moving the price much.

Why this matters before we touch any math

The number-one reason retail traders lose money is misidentifying their role. They believe they're speculating with edge — a real, repeatable advantage over other participants. In reality they're paying the spread to market makers without any informational advantage at all. Throughout this curriculum, every strategy we discuss will ask: who's on the other side of this trade, and why is it good for them?

Predict before the next lesson

Tomorrow we'll cover the menu of instruments — equities, bonds, futures, options. Before we do:

• Which of those four instrument types do you think has the most participants overall (by number of distinct buyers and sellers)?
• Which has the largest dollar volume traded?

Write your guesses in a note (no peeking). We'll check tomorrow.