Win rate is noisy. You can bet brilliantly and lose for months, or badly and win for weeks — variance drowns the signal over any short sample. Closing line value (CLV) cuts through it: it measures whether you consistently beat the market's *final* price. It's the metric sharps trust most.
What closing line value is
The closing line is the price an outcome trades at right before the event starts — the market's sharpest, most-informed number. If you took a better price than the close, you have positive CLV. Bet a team at 40% implied and it closes at 45%? The market moved toward your side after you were on it. Do that repeatedly and it's near-proof you're finding real value, not luck.
Why it beats win rate as a signal
Outcomes are binary and random; the closing line is the market's collective verdict on your probability. Positive CLV shows up in far fewer bets than a win rate needs to become meaningful, because you're measured against a sharp benchmark on every bet, not just the ones that happened to land.
How Momus uses it
Momus freezes the odds it takes when it enters, then compares them to where the line closes. Positive CLV across a run is the honest evidence that the model's edge is real and repeatable — independent of any single win or loss. It's tracked alongside win rate and P&L on the track record.
Pair it with how Momus finds value on Polymarket to see where that edge comes from in the first place.