# Closing line value

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Canonical: https://novigapi.com/learn/closing-line-value

Closing line value is how much better the price you took was than the final fair price just before the event started.

```
CLV = p_close_fair / p_bet - 1, where p_bet is the implied probability of the price you took
```

Closing line value, or CLV, compares the price you got to the price at the close, the last moment before trading stops. The closing price is the market's most informed estimate, because it has absorbed every injury report, lineup and sharp bet. If you consistently get better prices than the close, you are almost certainly betting with an edge, even through a losing streak. That is why serious bettors track CLV more closely than short-run profit.

## How it works

Devig the closing market to get its fair probability for your side. Compare it to the implied probability of the price you took. If the closing fair probability is higher than your bet's implied probability, you got a better price than the market's final view, and the ratio estimates your expected return. If the close agrees with the true probability, a bet with 5% CLV has an expected return of about 5%.

## Worked example

Measuring CLV

| Case | Price taken | Implied at bet | Closing fair | CLV |
| --- | --- | --- | --- | --- |
| Sportsbook moneyline | +120 | 45.455% | 48.000% | +5.60% |
| Novig Yes contract | 42.0% | 42.000% | 47.000% | +11.90% |
| Novig Yes contract | 53.0% | 53.000% | 52.000% | -1.89% |


In the first row, 0.48 / 0.45455 - 1 = 5.60%. In the second, buying Yes at 42% when it closed at a fair 47% gives 0.47 / 0.42 - 1 = 11.90%, a move from about +138 to +113 in American odds. The third row is negative CLV: the market closed against you. The [CLV calculator](https://novigapi.com/clv-calculator) does this for any format.

## On Novig

Novig is a strong closing benchmark because its prices are set by traders, not a house margin, and its fair midpoint needs no devigging beyond the spread. Our `/clv` endpoint scores a list of entries against Novig's closing fair price, and `/line-history` gives the intraday path so you can see when the move happened. Novig's free daily CSVs at data.novig.com start 3 Aug 2026 and carry no player or team names; we join names and add intraday history from our own snapshots.

## Common mistakes

- Measuring against the closing price with the vig still in it. Always compare to a devigged close.
- Using a thin market's close. A market with little volume can close at a stale price.
- Judging CLV on ten bets. It is a statistical signal and needs hundreds of bets to separate skill from noise.
- Ignoring fees. A live Novig fill pays the taker fee, which lowers the return CLV promises.

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