Market Making and Liquidity Provision › Summary

This chapter examined quantitative market making from its economic foundations through model design and risk management:

Core economics: You earn the bid-ask spread by providing immediacy to other traders. You buy at the bid and sell at the ask, capturing the difference. Profitability depends on managing inventory risk and avoiding adverse selection.

Inventory risk: Accumulated positions expose you to directional price risk. The Avellaneda-Stoikov model provides optimal quotes that shift based on inventory, encouraging mean reversion. When long, quotes shift lower; when short, quotes shift higher.

Adverse selection: Informed traders profit at your expense by trading when they have superior information. Spreads must be wide enough to compensate for losses to informed flow while remaining competitive for uninformed flow.

The Avellaneda-Stoikov model: This foundational framework produces optimal bid and ask quotes based on current inventory, volatility, risk aversion, and time horizon. The model introduces the reservation price concept: your private valuation adjusted for inventory risk.

Risk management: Practical market making requires position limits, volatility regime detection, and end-of-day protocols. The model parameters require careful calibration and ongoing monitoring.

Technology and speed: Modern market making is a technology race. Latency determines adverse selection exposure; if you are slower, you face higher costs from stale quotes being picked off. The upcoming chapter on High-Frequency Trading will explore these technological dimensions further.

Implementing a market-making strategy requires both financial modeling and engineering. The models provide a theoretical foundation, while the operational and technological constraints of modern electronic markets determine whether the strategy works in practice.