# Line movement

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Canonical: https://novigapi.com/learn/line-movement

Line movement is any change in a market's price or point line between when it opens and when it closes.

Line movement is the change in a price over time. A spread can move from -3 to -3.5, a total from 47.5 to 49, or a moneyline from -120 to -140. Lines move because of new information, such as injuries, lineups and weather, and because of money: sportsbooks adjust to balance risk or to follow respected bettors, and exchange prices move when traders hit orders. Tracking line movement is how bettors spot steam, reverse line movement and middles, and how they measure closing line value.

## How it works

A market opens with a first price, often set by a sharp book or the first traders on an exchange. Early limits are low, so the first sharp bets move it most. As the start nears, limits rise and more information arrives, and the line usually becomes more accurate. The final price before the start is the closing line. Comparing your price to it, after removing the vig, tells you whether you got value.

## Worked example

An illustrative moneyline on Novig, shown as the fair Yes price from open to close:

Line movement from open to close (illustrative)

| Snapshot | Fair Yes | American | Move since open |
| --- | --- | --- | --- |
| Open, 9:00 | 52.0% | -108.3 |  |
| Injury news, 11:30 | 53.5% | -115.1 | +1.5 pts |
| Lineups, 17:00 | 55.0% | -122.2 | +3.0 pts |
| Steam, 18:45 | 57.0% | -132.6 | +5.0 pts |
| Close, 19:05 | 58.5% | -141.0 | +6.5 pts |


A trader who bought Yes at the open at 52% and saw it close at a fair 58.5% has closing line value of 0.585 / 0.52 - 1 = 12.5%. Measure your own entries with the [CLV calculator](https://novigapi.com/clv-calculator).

## On Novig

Novig's free daily CSVs at data.novig.com, which start 3 Aug 2026, record trades but not the intraday path of each market's bid and ask, and they carry no player or team names. novigapi.com adds intraday line history from our own snapshots: `/line-history` returns the price path for a market, `/line-moves` lists moves over a threshold, and webhooks fire on line moves, steam, market open and settlement. On paid plans REST data is at most about 10 seconds old; the stream pushes changes within 5 to 30 seconds. On Novig, a move in percentage points converts directly to a probability change, so a move from 52% to 58.5% is 6.5 points regardless of which side you read.

## Common mistakes

- Reading every move as sharp action. Books also move on their own liability, and thin exchange markets move on single orders.
- Comparing American-odds moves across favorites and underdogs. Ten cents near even money is a bigger probability change than ten cents on a heavy favorite; compare in probability.
- Chasing moves that are complete. Value comes from moving before the market, not after.

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