A sportsbook's price at kickoff reflects everything the market knows: injuries, weather, lineup news, and the weight of sharp money. If you consistently bet a side at a price better than where it closes, you are systematically finding value before the market corrects. Over a large sample, positive CLV tracks profit far more reliably than the win/loss record of any single week, which is dominated by variance.
You bet Team A at +105 on Tuesday. By kickoff on Sunday, the consensus price on Team A has shortened to -110.
# Convert both prices to implied probability Your price +105 -> 100 / (105 + 100) = 48.8% Closing line -110 -> 110 / (110 + 100) = 52.4% # You bought the side ~3.6 points of probability cheaper # than where the sharp market settled. That is positive CLV.
The line moving toward your side after you bet is the signal: the market agreed with you and repriced. Even if Team A loses this particular game, repeatedly beating the close this way is what compounds into an edge.
ParlayAPI keeps the closing prices you need to grade CLV yourself. The historical archive holds 1.7M+ historical closing lines with continuous depth back to 2005 (as of 2026-08), served from
/v1/historical/sports/{sport_key}/odds. Pull the closing consensus for the event you bet, compare it to your entry price, and you have your CLV. For live grading, /v1/verdict reports how a line has moved since you would have bet it, and /v1/meta/movers ranks the day's biggest line movements so you can see which of your positions the market has since agreed with.