Most retail traders assume price discovery is a neutral, frictionless process — that the market simply finds fair value. That assumption is expensive. The mechanism by which prices are set varies dramatically between venues, and those structural differences directly affect the spread you pay, the fills you receive, and the liquidity available when you need it most.

In a dealer or market maker system, a designated participant continuously quotes bid and ask prices, standing ready to buy or sell from their own inventory. The market maker profits from the spread between those two prices. This creates constant liquidity, but it also means price is not purely a function of supply and demand — it reflects the dealer's risk appetite, inventory position, and hedging activity at any given moment.

CONCEPTMarket makers provide continuous liquidity by quoting both sides — but the spread is their profit margin, paid directly by you on every trade.
WARNINGWide spreads during volatile sessions signal dealer inventory stress — execution quality deteriorates precisely when you want to move quickly.
KEY IDEAAuction markets centralise all orders into one pool — price emerges from actual competing bids and offers, not a dealer's quote.

Auction markets operate differently. All buy and sell orders flow into a central order book, and price is determined by matching the highest bid with the lowest offer. The ASX operates as an order-driven auction market during continuous trading. There is no single dealer setting the price — the crowd does. Historically, this structure produces tighter spreads in liquid names but can gap aggressively when order flow is one-sided.

Bid-Ask Spread: Market Maker vs Auction MarketMarket MakerAuction MarketWideSpreadTightSpreadTypical spread profile under normal market conditions

The practical implication for active traders is this: knowing which structure you are trading inside shapes how you interpret price action. A widening spread in a market maker venue often signals the dealer hedging risk — a structural tell rather than fundamental news. Traders who study execution mechanics often reference the market maker definition on Investopedia as a starting point, alongside the broader concept of order book dynamics on Wikipedia and auction market theory on Investopedia to build a complete picture of venue structure.

The market does not care whether you understand how it sets prices — but the traders who do consistently make more informed decisions about where and how they execute.

This content is for educational purposes only and does not constitute financial product advice. Past performance is not indicative of future results. Profit Logic Ltd (ACN 688 669 936) accepts no responsibility for errors or omissions in this content or anywhere on this website. Always seek advice from a licensed financial adviser before making investment decisions.