What a market maker does (definition first)
A market maker is an entity that provides two-sided quotes—a price to buy and a price to sell—so others can trade without always finding a direct counterparty at that same moment. In many markets, the market maker earns primarily through the spread (the difference between bid and ask) and through managing the risks that come from holding positions.
In practice, this usually involves one or both of these mechanisms:
- Inventory management: the market maker’s net position can change when clients trade.
- Hedging or risk offset: the market maker may try to reduce exposure by trading elsewhere or using other risk-management methods.
Because these mechanisms depend on market conditions, “how good” a market maker is can’t be judged from one number alone; it depends on how costs and execution behave across scenarios.
Evidence and due-diligence checklist
Use the items below as a verification checklist. The goal is to gather facts you can explain to someone else, not to pick a “best” provider.
- Quote and execution transparency
- Check what the provider says about how quotes are produced and updated.
- Look for clear definitions of terms such as bid/ask, spread, re-quotes, and execution methods.
- Evidence to look for: policy documents and platform or execution documentation that describe the operational process.
- Costs you can actually account for Trading costs are more than headline spread. Verify how the provider measures and applies costs, including:
- Typical and worst-case spread behavior (especially during volatility)
- Any additional fees or pricing components that may apply
Assumption for any example you run: you need to assume a spread and a holding time, because costs accumulate with the path of fills. Without those assumptions, comparisons are not verifiable.
- Consistency of price availability under stress (failure-mode thinking) Material failure modes are usually revealed in fast or illiquid conditions. Ask:
- What happens to quotes during high volatility?
- Are trades delayed, re-priced, or otherwise not filled as expected?
Example assumption: suppose you place an order expecting an immediate fill at a quoted price; if the quote changes between submission and execution, your realized price may differ. The relevant check is whether the provider’s documentation clearly explains how this is handled.
- Conflict-of-interest and incentives Market makers can have incentives that differ from a client’s objective because the provider can benefit from certain trading outcomes (for example, through spread and risk management). Check for:
- How the provider describes conflict-of-interest management
- Whether the provider’s disclosures explain how client orders interact with the provider’s own risk controls
Even without assuming wrongdoing, mismatched incentives can still produce poorer execution in certain conditions.
- Order handling rules and dispute clarity Look for clear, testable explanations of:
- Order types and how they are treated
- What “best effort” means, if used, and what the provider still may do when conditions change
- Dispute or complaint handling procedures
This matters because “what you experienced” is often determined by these rules, not by marketing language.
Limitations, risks, and what not to assume
A checklist works only if you respect these limitations:
- No real-time guarantee: you cannot assume stable spreads, immediate fills, or predictable price behavior at all times.
- Historical relationships don’t ensure future results: execution patterns observed in past periods may not repeat, especially when volatility regime changes.
- Provider conditions can vary: execution quality can change with market liquidity, internal risk limits, technology load, or external liquidity.
One material limitation to explicitly test is quote-to-execution risk: the difference between the price you saw and the price you actually received. Another common failure mode is widening spreads and re-quotes when the market moves faster than the system can refresh or manage risk.
Finally, treat “liquidity” as a concept with a practical test: even if quotes are present, they may be less favorable during stress.
Verification method and next questions
To verify your conclusions independently:
- Collect documents that describe execution and pricing mechanics. 2) Write down your assumptions (example: assumed spread, expected fill timing, order type behavior) before comparing any observations. 3) Look for evidence that addresses stress behavior, not only typical conditions.