Glossary term
Consolidated Quotation System (CQS)
The Consolidated Quotation System is the CTA market data feed that disseminates consolidated quote information for Network A and Network B securities.
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What Is the Consolidated Quotation System (CQS)?
The Consolidated Quotation System, or CQS, is the CTA market data feed that disseminates consolidated quote information for Network A and Network B securities. It carries bid and offer information rather than completed trade prints.
CQS is part of the public market-data infrastructure that helps market participants see displayed quotation information across participating venues.
Key Takeaways
- CQS disseminates consolidated quote information.
- It is distinct from CTS, which disseminates last-sale trade data.
- CQS supports bid and offer visibility for Network A and Network B securities.
- Quote data helps form market displays, NBBO-related workflows, and execution analysis.
- Recent SIP changes include odd-lot quote information in the consolidated quote environment.
How CQS Works
Participating venues send quotation messages to the SIP. CQS processes and disseminates quote information to subscribers. Those subscribers may include brokerages, data vendors, trading firms, and systems that need quote data for display, routing, compliance, or analytics.
Quote data changes constantly because bids and offers update as orders enter, cancel, execute, or move across venues. That makes CQS a high-volume, latency-sensitive part of the market data stack.
CQS Versus CTS
System | Primary data |
|---|---|
CQS | Quotes, including bids and offers. |
CTS | Last-sale trade reports. |
CTA Plan | Governance framework for Network A and B consolidated data. |
Practical Interpretation
CQS matters because trading decisions often depend on the best available bids and offers, not just the last trade. A last sale may be stale in a fast market, while quotes show where buyers and sellers are currently willing to trade.
Quote data also affects execution-quality measurement. Metrics such as effective spread and price improvement rely on comparing fills with quote benchmarks, often including midpoint or NBBO references.
Quote Quality and Execution
Because CQS handles quote information, it is directly connected to how market participants understand the displayed market. A quote can influence whether an order is marketable, whether a broker can claim price improvement, and how execution quality is measured against the midpoint or NBBO.
Quote feeds also have operational importance. If a market-data subscriber cannot process changes correctly, it may display stale or incomplete information. That is why changes to CQS specifications, such as odd-lot quote updates, matter to vendors and trading systems as well as exchanges.
CQS is also important because quotes can change without trades occurring. A market may become more expensive to buy or sell before the last sale changes. That makes quote data a forward-looking view of available liquidity, while trade data is a record of completed transactions.
For execution review, CQS-derived benchmarks help explain whether a fill was inside the spread, at the quote, or worse than the displayed market.
The Bottom Line
CQS is the consolidated quote feed for CTA-covered securities. It helps turn many venue-level bid and offer updates into market-wide quotation data that supports trading, display, compliance, and execution analysis.