7. Market types III, specials

BTTS, correct score, half-time/full-time

BTTS (both teams to score) is a simple yes/no question: do both teams score. It is important to see that this is not a separate world: it is priced from the same goal distribution as Over/Under (chapter 5), just covering a different slice. The goal distribution is no more complicated than a list of chances: every possible result has a number next to it saying how often it happens, 1-1 often, 4-3 rarely. In a 2-0 there were two goals, so Over 1.5 (more than one and a half goals) came in, but BTTS did not, because the away team did not score. In a 1-1 it is the other way round: two goals again, so Under 2.5 (fewer than two and a half goals) came in, and so did BTTS, because both teams found the net.

On the correct score market you tip the final result (2-1, 1-1, 0-3...). Many outcomes, high multipliers, and precisely because of this a comfortable terrain for the bookmaker: among the many outcomes a thick margin can be spread out unnoticed. The margin (also called overround, all the same thing) is the commission built into the odds. If you convert the offered odds into chances and add them up across all the outcomes of the market, you never get exactly 100%, always more, and that surplus above 100% belongs to the bookmaker. On correct score this surplus is often above 20%, versus the typical 5% of 1X2. In concrete terms: out of every €100 staked, on average roughly €17 stays with the bookmaker on correct score, and roughly €5 on 1X2.

Half-time/full-time (HT/FT) combines the two states: nine outcomes from 1/1 to 2/2. Nine, because each of the three half-time standings (1, X, 2) can be followed by three different final results, and 3 times 3 is nine. X/1, for example, means a draw at half-time and a home win at the end. The temptingly high multipliers here too come from the natural mathematics of combined, low-probability outcomes, topped up with a generous margin. Two things have to happen at once, the half-time standing and the final result, and two conditions come together less often than one. Suppose the chance of a half-time draw is 25%, and that after a drawn first half the home team turns it around in 40% of cases. The two multiplied give 10%, that is roughly one such match in ten: the fair odds would be 10, while the posted odds are lower, and the difference is the bookmaker’s margin.

A special market is not special because it works by a different logic: behind it is the same distribution of chances, only cut in a different place. What makes it different: a lot more margin fits on the slicing.

Corners, cards, player props

The corner and card markets (Over/Under on the corner count, on yellow cards) look at first glance like statistical playgrounds, but are in fact strongly context-dependent: the corner count depends on playing style, the card count on the referee and the stakes of the match. A meaningless, lukewarm match and a derby with the same teams produce a completely different number of cards: in one there are typically two or three yellows, in the other six come easily. So the very same "Over 4.5 cards" line rarely comes in on one match and is realistic on the other, even though the wording on the slip is word for word identical.

Player props, that is bets on the performance of one individual player (goalscorer, number of shots, assists), are the fastest-growing segment. From the bookmaker’s perspective they are among the best deals: there is little reliable public data, news (injury, rotation, position change) reprices the market within hours, and the margin is wide even by comparison. Whoever plays props is at a double disadvantage. They know less about the match than the bookmaker, because the bookmaker has repriced the injury and rotation news before anyone can act on it, and at the same time they buy the bet more expensively than usual: with a much bigger margin than the typical 5% of 1X2.

A side market (or special market) is what is not the main question of the match: not 1X2 and not the number of goals, but for example corners, cards or the goalscorer. Here a "good feeling" is an especially cheap signal: everyone has an impression of the corner count or the goalscorer, but few actually know how often 8, 10 or 12 corners really occur. The gap between the impression and the real frequency, that is the reliable distribution, is built into the price by the bookmaker, to its own benefit.

Why is the margin higher on side markets?

Three reasons. First: turnover is small, so the bookmaker covers the risk of pricing errors with a wider margin. Second: competition is weak: on a side market you rarely compare five bookmakers, on the main markets you do. Third: modelling is harder, meaning it is harder to estimate the true chances, because the data is scarcer and noisier, that is more erratic. The same team takes 3 corners in one match and 11 in the next, and the fact that there were plenty in three matches tells you nothing certain about the fourth. The bookmaker is uncertain too, and you pay for this uncertainty as well.

The numbers are tangible: if the total margin is 5% on 1X2 and 22% on correct score, then 22 divided by 5 is roughly four, so turning over the same money on the correct-score market is roughly four times more expensive. With the method of chapter 4 you can calculate the margin of any market. And the platform’s match page shows the provider’s 150+ markets automatically with opening, average and best prices (chapter 40): the opening price is the one the bookmaker started with, the average price is the average across several bookmakers. There this is visible to the naked eye.

The lesson is not that side markets are forbidden, but that there the bet is the most expensive, that is the margin built into the odds is the biggest, and there you know the least compared with the bookmaker. If you play them, treat it as entertainment, and know how much you are paying for it.