What Is a Steam Move?
A steam move is a rapid, synchronized price change across multiple sources within a short time window (typically minutes). It's one of the clearest signals of coordinated sophisticated activity.
When we first implemented steam detection at OddsFlow, the predictive power surprised us. These aren't just price changes—they're information events.
Characteristics of Steam Moves
Speed: Prices move within 5-15 minutes across multiple sources
Magnitude: Typically 10-20+ basis points (e.g., 1.90 → 2.00)
Synchronization: Multiple independent sources move in the same direction
Timing: Often occurs when new information enters the market
How We Detect Steam
At OddsFlow, we monitor prices across sources and flag potential steam when:
- 1Price moves >X% within Y minutes
- 2Movement is corroborated by N+ independent sources
- 3Movement persists (not immediately reversed)
The specific thresholds vary by league and market type. Major leagues require larger moves to qualify as steam due to higher baseline volatility.
Steam as a Model Feature
We use steam detection in several ways:
Binary feature: Did steam occur on this match? (Yes/No)
Directional feature: Which side did steam favor?
Timing feature: How long before kickoff did steam occur?
Magnitude feature: How large was the coordinated move?
Early-occurring steam (>12 hours before kickoff) tends to be more informative than late steam.
Important Caveats
Not all steam is signal. Some causes:
- Lineup leaks (information-driven, valuable)
- Large recreational accumulation (volume-driven, less valuable)
- Coordinated but misinformed activity (noise)
We've learned to weight steam signals by context, not treat them as binary indicators.
📖 Related reading: Odds Movement Analysis • Market Participant Types
*OddsFlow provides AI-powered sports analysis for educational and informational purposes.*