Steam
Steam refers to sudden, rapid line movement across the entire sports betting market. When steam hits, multiple sportsbooks adjust their lines within minutes—sometimes seconds—in the same direction.
What Causes Steam
Steam typically indicates one of two things:
Syndicate action. A betting syndicate—a coordinated group of sharps—has unloaded significant money across multiple books simultaneously. The coordinated pressure forces market-wide adjustment.
Breaking information. Major injury news, lineup changes, or other market-moving information has hit. Books scramble to adjust before being arbitraged.
Anatomy of a Steam Move
Here's what steam looks like in real-time:
- Pre-steam: Chiefs -3 across all major books
- T+0 seconds: Sharp money hits 3-4 books simultaneously
- T+30 seconds: First books move to Chiefs -3.5
- T+2 minutes: Entire market at Chiefs -4 or higher
- Stabilization: New consensus around Chiefs -4.5
The whole process can take under 5 minutes. If you're not watching in real-time, you miss it entirely.
Trading Steam
Professional bettors have two approaches to steam:
Front-running. If you can identify steam early (the first 30 seconds), you can bet at other books before they adjust. This requires real-time odds feeds and fast execution.
Following. Some bettors track steam moves as signals, betting in the direction of the steam at the new price. The theory: if sharps moved it, the new line may still have value.
Both approaches have diminishing returns as more bettors compete for the same edge.
Steam vs Regular Line Movement
Not all line movement is steam:
| Steam | Regular Movement |
|---|---|
| Multiple books simultaneously | One book at a time |
| Minutes or less | Hours or days |
| Sharp money or news | Public money accumulation |
| Often 1+ points | Usually half-points |
Regular movement from public betting is gradual and predictable. Steam is sudden and market-wide.
Why Steam Matters for Prediction Markets
On Kalshi and Polymarket, the equivalent of steam is a rapid price move across all order books—usually triggered by news events or large orders.
If you can identify stale lines before steam hits, you capture CLV. This is the core thesis behind algorithmic edge detection: finding prices that haven't adjusted to new information yet.
Related Terms
- Sharp — Professional bettors who generate steam
- CLV — Capturing value before steam moves the line
- Reverse Line Movement — Sharp money moving lines opposite to public betting
- Stale Line — Prices ripe for steam correction
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