Plain-English definitions of the market terms we use across the site. This is a reference for what the words mean — not advice on what to bet. Everything Nebula publishes is information beside the market, never a pick. For how our numbers are built and graded, see the methodology.
A bet on which side wins the game outright, priced as American odds (e.g. −140 or +120). A negative number is the favorite (how much you'd stake to win $100); a positive number is the underdog (how much $100 would win).
On our board we show the market moneyline; for MLB we add a calibrated win probability beside it, as information — never a recommendation.
Baseball's version of a point spread, almost always set at 1.5 runs. To "cover", the favorite (−1.5) must win by two or more; the underdog (+1.5) covers by winning outright or losing by exactly one.
We publish the market run line only. Our own testing found no reliable signal against it, so we add no cover projection.
A market on the combined score of both teams. The book posts a number; the question is whether the final total lands over or under it. It has nothing to do with who wins.
For MLB we show our independent projected total beside the market's number, so you can see when they disagree — and by how much.
A margin-of-victory handicap. The favorite "gives" points; the underdog "gets" them. Whether a side covers depends on the final margin versus the posted number.
The book's built-in commission, baked into the odds on both sides of a market. It's why the two prices on a game imply a combined probability above 100% — the extra is the house's margin.
The win probability baked into a price, before the vig is removed. Converting odds into a probability is what lets you line the market up against an independent estimate.
The first price a book posts on a market. It's a clean, early snapshot before the day's money and news move things.
We grade our projections against opening lines — an honest, well-defined benchmark that doesn't shift under us.
The final price just before an event starts. It has absorbed all the information and money that moved the market, and is widely treated as the sharpest number available.
The difference between the price you recorded and the closing line. Regularly landing a better number than the close is a common way people gauge their process — though it is a proxy, not a guarantee of profit.
More detail lives in our CLV guide.
Removing the book's commission from a market to estimate the "fair" probabilities the odds imply. It's a comparison tool for reading a price, not a signal to act.
Our independent estimate for a game — a projected total, or a calibrated win probability — built only from team, player, park and schedule data, never from the betting line. It's information shown beside the market, not a pick.
How it's built and how accurate it is: see the methodology and track record.
How well stated probabilities match reality. A well-calibrated model that says 55% is right about 55% of the time. We calibrate our outputs so the numbers don't overstate confidence.
Definitions are provided for information only and are not betting advice. Nebula Insights publishes no picks, leans, or bet recommendations. 18+ only. If gambling is a problem for you, call 1-800-GAMBLER.