Reference · Liquidity and Market Data
Liquidity Aggregation: Combining Quotes and Capacity
Combine illustrative provider quotes while preserving source, size and timestamps, with checks for shared liquidity, permissions and routing rules.
Published Updated
Published by FxTrusts, a supplier of brokerage and prop firm technology. Prepared with AI-assisted research and drafting; reviewed against the cited public sources. Examples are illustrative. Product links describe our services.
What is Liquidity aggregation?
Liquidity aggregation combines eligible quotes or routes from multiple sources into a view or execution process. It requires normalized instruments, quantities and timestamps. Adding providers does not automatically create independent capacity, guarantee the best possible fill or establish permission to trade through every source.
Normalize before comparing prices
A EUR/USD symbol from two providers may differ in quantity units, precision, contract terms or account eligibility. Map those fields before sorting quotes by price. The same ticker text is insufficient. A usable aggregate record retains source identity, instrument mapping, bid or ask side, price, available quantity and freshness. Dropping the source during normalization makes it harder to investigate an execution or remove a faulty input later.
Separate a combined display from an execution policy
A best-price display can show an attractive quote that an account cannot use because of credit, size, agreement or session constraints. A router needs an eligibility policy as well as a price comparison. Commission and other terms can also change a like-for-like assessment. The FX Global Code provides wholesale-market disclosure context, while the actual supplier agreements and system configuration determine the permitted routes for a particular deployment.
Avoid treating correlated sources as independent depth
Two streams may ultimately reflect overlapping liquidity or the same underlying venue. Their quantities cannot always be added as if they were independent promises. Simultaneous requests can also alter what remains available. Describe whether the aggregate is indicative, executable, fully disclosed or otherwise conditioned by the source model. A capacity claim requires its own evidence; the number of connected feeds is not a substitute for that evidence.
Retain enough state to remove a bad input
A source can become stale, send an invalid price or lose one side while other streams remain healthy. The system needs a documented rule for excluding, flagging or recovering that input. Keep timestamps and update identifiers through the aggregation layer. When investigating a wrong price, reconstruct the input set and eligibility decisions rather than only the final merged quote. The cTrader FIX specification illustrates instrument, price, size and entry-identifier fields within that platform’s dialect; it does not document a multi-provider aggregator or prove any FxTrusts implementation.
Three eligible quotes under a declared model
Assume three independent sources quote the same linear instrument in the same units, and all listed prices remain available. A 50-unit buy uses 20 units from A at 10.00 and 30 from B at 10.02, giving 500.60 divided by 50, or 10.012. Source C is not selected in this simplified price-only example. Real routing must also apply the agreed eligibility and cost rules.
| Source | Ask | Available units | Illustrative selection |
|---|---|---|---|
| A | 10.00 | 20 | 20 units |
| B | 10.02 | 40 | 30 units |
| C | 10.04 | 60 | 0 units |
Implementation checklist
- Normalize contract, currency, quantity and precision before sorting quotes.
- Retain source identity and timestamps in the merged record.
- Check eligibility and overlapping liquidity before adding capacity.
- Define stale-source removal, recovery and execution-review evidence.
Sources
These documents support the reference. Check the original publication for current requirements and the limits of its scope.
- cTrader FIX API specification: platform-specific market datahelp.ctrader.com
- FX Global Codewww.globalfxc.org
- MetaTrader 5 price datawww.metatrader5.com
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