Point Spread Betting

The point spread is the defining market of American football and basketball betting. It exists because a moneyline on a mismatch is boring: nobody wants to lay −2000, and the book does not want to book it.

How it works

The favourite gives points, the underdog receives them. A team at −6.5 must win by seven or more for the bet to cash. The other side wins if that team loses, ties, or wins by six or fewer.

Because the number is chosen to split the action, both sides typically price around −110. The whole market becomes a question of whether the number is right, not who wins the game.

Covering

A team covers by beating the spread. Crucially, a team can win the game and fail to cover, or lose and cover — which is the entire point of the market. Against-the-spread records describe performance relative to expectation rather than in absolute terms, which is why a mediocre team can have an excellent ATS record.

The half point

Most spreads carry a half point — the hook — which makes a push impossible and forces a win or a loss.

Its value depends entirely on where it sits. In football, margins cluster hard on 3 and 7, so a half point crossing those numbers is worth several times a half point elsewhere. Key numbers works through the arithmetic; the short version is that −2.5 and −3.5 are very different bets while −5.5 and −6.5 are nearly the same one.

Buying and selling points

Many books let you move the spread in your favour for a worse price, or the other way for a better one. The price is typically 10 cents per half point, rising sharply — often to 25 cents or more — around key numbers.

That premium usually exceeds the half point's actual value. Books know precisely what those crossings are worth and price them to profit. Compare what you are paying against how often the crossed margin genuinely occurs before assuming a purchase is good.

Alternate spreads

Rather than buying incrementally, you can take a completely different number at a completely different price: a −7 favourite at −2 for a much shorter return, or out at −13 for a longer one.

These are useful when your view is about how a game goes rather than whether. They also derive from the same underlying distribution as the main line, so if the main line is efficiently priced the alternates usually are too.

Sport by sport

Football — spreads are the primary market and key numbers dominate.

Basketball — spreads are primary and margins are close to smoothly distributed, so half points are worth roughly the same everywhere.

Baseball and hockey — the spread is fixed at 1.5 (the run line and puck line) with the price doing the work instead of the number.

Soccer — Asian handicaps use quarter-goal increments and split stakes across two outcomes, which handles the draw without a separate market.

How WeBall grades spreads

Scoring margin is fitted with a normal approximation and shrunk toward the market's de-vigged price in proportion to sample depth. Alternate spreads derive from the same fitted distribution, so the main line and the alternates cannot contradict each other.