CobiaNBA Moneyline Betting on Prediction Markets
Short answer: An NBA moneyline on a prediction market is a share on one team to win the game, priced from 1 to 99 cents. The share pays $1 if the team wins. A 75 cent share means the market gives that team about a 75% chance, and you need that team to win more than 75% of the time at that price to come out ahead.
Moneyline in one paragraph
A moneyline bet picks the winner of the game with no point spread. At a sportsbook, a favorite shows as -300 and an underdog as +240. On Polymarket the same game shows two shares, for example 74 cents for the home team and 27 cents for the visitor. The two prices add to slightly more than $1 when the spread is wide, and close to $1 when the market is liquid. If you need a refresher on American odds, see how to read betting odds.
Converting between the two
A price in cents is an implied probability. To compare with a sportsbook, convert the American odds:
- For a favorite at -300, the implied chance is 300 / (300 + 100) = 75%.
- For an underdog at +240, the implied chance is 100 / (240 + 100) = 29.4%.
Those two add to 104.4%. The extra 4.4 points are the sportsbook's margin, which is why removing the vig matters before you compare. A Polymarket quote has no built-in margin. Its cost shows up as the gap between the bid and the ask.
Why heavy favorites cost more than they look
Say you buy a team at 88 cents. You win 12 cents if they win and lose 88 cents if they lose. You need to be right about 88 times in 100 just to break even. NBA favorites do win often, but the price already knows it. Breakeven is the entry price, and a high hit rate at a high price can still lose money. That is the idea behind how Cobia grades in units, where we show the entry price beside every hit rate.
What moves an NBA price
- Injury news. A star ruled out an hour before tip can move a price 10 cents. Check the injury report and the starting lineup.
- Back-to-backs and travel. The second night of a back-to-back is a real, measurable drag, and the market knows it.
- Rest days and load management. Early in the season teams sort out their rotations. Expect noisy lines in the first weeks.
- Live scoring. Prices move on every run. A 12 point lead can flip in three minutes.
Moneyline or spread
The spread asks "by how many points", which is a different question from "who wins". Spread markets on prediction markets exist for many games but are thinner. If you only have an opinion about the winner, the moneyline is the cleaner bet. If you think a favorite wins comfortably, the spread pays better but adds the variance of a margin. Our explainer on moneyline, spread and totals covers the trade-off.
Checking Polymarket against a sportsbook
For every NBA pick we post, we store the Bovada, Pinnacle or DraftKings moneyline from the time the pick was posted and show it beside the Polymarket price. If Polymarket is 3 cents cheaper than the sportsbook after you remove the vig, that is a reason to look closer. If it is 3 cents more expensive, the sportsbook is probably the better place for that bet. Details are in Polymarket vs sportsbook odds.
A short example
Say the visiting team trades at 31 cents and the home team at 71 cents. The two add to 102 cents, so there is a two cent spread across the pair. If you think the visitor is closer to a 35% chance, buying at 31 cents has a small edge on paper: 35 minus 31 is 4 points. If you are wrong about the visitor's chance by those same 4 points, the edge is gone. Small edges need many bets to show up, and a few weeks of results will not tell you who was right.
That is also why we avoid presenting a win probability as an independent forecast. It usually sits close to the market price, and the honest way to judge a pick is the graded record in units.
Before you buy
- Read the market title to confirm it is the full game moneyline and not a first half or quarter market.
- Check the best ask, not the last price.
- Check the injury report and lineup.
- Decide the most you are willing to lose and size to that. Kelly sizing is one method, with the warning that it assumes you know your true edge.
Our NBA hub lists the day's games with the Polymarket price and sportsbook line side by side, and the track record page grades every NBA pick we posted.
Key takeaways
- The price in cents is the implied win probability.
- Sportsbook odds carry a margin, so remove the vig before comparing.
- At 88 cents you need to win 88% of the time to break even.
- Injuries and back-to-backs move NBA prices the most.
- Buy at the ask, and check that the market is the full game moneyline.
FAQ
What is an NBA moneyline on Polymarket?
It is a share on one team to win the game. The share pays $1 if the team wins and nothing if it loses, and its price in cents is the market probability.
How do I convert -300 odds to a Polymarket price?
Divide 300 by 400 to get 75%, which is about a 75 cent share. The sportsbook figure includes a margin, so a fair comparison removes the vig first.
Is the moneyline better than the spread?
Neither is better by default. The moneyline answers who wins, and the spread answers by how much. Pick the one that matches your opinion.
Why is the favorite so expensive?
Because the market already expects the favorite to win. A high price means you risk a lot to win a little, so a high hit rate does not guarantee a profit.
Does Cobia post NBA picks?
Yes. NBA picks are graded in public against the final result, in units at 1 unit per pick, with the entry price shown.
Cobia grades every pick in public, losers included.
Units at 1 unit per pick, with the entry price beside the hit rate.
See the track record