Teaser Math and Wong Teasers

A teaser is a parlay with a bribe. You move each leg's spread several points in your favour, and in exchange you accept much worse odds and still need every leg to win.

The breakeven arithmetic

A standard two-team six-point teaser pays around −120. That requires winning about 54.5% of the time overall — which, since both legs must win, means each leg needs to hit roughly 73.9%.

So the question for any teaser is simple: does moving this spread six points push each leg above 74%? For most spreads it does not come close. Six points off a −4 favourite takes you to +2, which is worth a lot but nowhere near enough to clear 74% on its own.

Why crossing 3 and 7 is different

The reason the Wong teaser exists is that margins are not smoothly distributed. Roughly 15% of NFL games land on exactly three points and 9% on exactly seven. A six-point move that crosses both numbers captures an outsized share of outcomes rather than a proportional one.

Two configurations do this:

Favourites from −7.5 to −1.5. The move crosses 7, 6, 5, 4, 3 and 2 — including both key numbers.

Underdogs from +1.5 to +7.5. The mirror image, crossing the same numbers in the other direction.

Teasing a favourite from −12 to −6, or an underdog from +8 to +14, crosses no key numbers and is simply a bad parlay.

What has changed

The Wong teaser was publicised widely enough that books responded.

Teaser pricing widened. Two-team six-pointers that once paid −110 now commonly pay −120 or −130, which raises the required per-leg rate from about 72.4% to over 75%.

Qualifying games got rarer. Books shade lines to avoid leaving spreads sitting in the −7.5 to −8.5 and +1.5 to +2.5 windows.

Some books restrict teasing key numbers entirely or apply different increments.

The logic still holds. The margin is much thinner, and whether a specific teaser clears the bar now depends on the price you are actually offered. Compute it rather than assuming.

Rules worth keeping

If you are going to teaser at all:

• Two teams only. Every extra leg raises the required per-leg rate sharply while the price barely improves.
• Only cross both key numbers. Favourites −7.5 to −8.5, underdogs +1.5 to +2.5. Nothing else qualifies.
• Check the actual price. At −130 the edge has usually evaporated.
• Avoid low totals. In games projected under about 42 points, margins distribute differently and the historical case weakens.

What WeBall does with them

Teasers combine legs, and the engine grades individual selections rather than combinations — so a teaser as a whole is not graded. What is graded is each underlying spread and its alternates, from the same fitted distribution.

Building the combination, and pricing the correlation between legs, is on the roadmap rather than in the product today.