Methodology

Favourite lost the first set

A favourite of 1.67 or shorter has dropped the opening set. That is the whole trigger. It is the spot itself that is worth seeing, not a judgement about whether the price has moved far enough - an earlier version demanded the live price beat the measured comeback rate before it would fire, and since the market almost never drifts that far after one set, the alert stayed silent at the moment it was wanted and went off much later when the match was nearly over. It fires the moment the set is lost, not when the price moves - it asks only that a price exists, never that it has drifted. An earlier version waited for a 10% move so the message would be sure to carry one; that made the alert wait on the market when the whole point is the scoreboard, and they arrived minutes late. The price now reaches the state before the set-completion event instead, so the alert is immediate AND priced. A match with no live price at all does not fire. After a first set that is rare and usually means the market is suspended - an injury being assessed - which is not a spot to be called into. The measured rate still travels with the message, as information: what favourites in this band do after losing a set, the fair price that implies, and how the price on offer compares. Read it as context, not as a recommendation - whether it is a bet turns on why the set was lost, and only watching can tell you that. The headline names the band rather than the price - Huge to 1.20, Large to 1.35, Big to 1.50, Medium to 1.67 - because a 1.05 shot falling over and a 1.60 one having a bad day are different alerts and should not read alike. Volume is about 33 a day across all tours at 1.67. Tighten the cap to 1.50 for roughly 23, or 1.35 for 13. A 6-0 or 6-1 opening set is the same alert with a different headline and a different table behind it - materially worse than an ordinary lost set at every price - rather than a rule of its own, so one match never sends two messages about the same event.

Favourite breaks back after a set and a break down

A favourite of 1.35 or shorter lost the opening set, went a break down in the second, and has levelled it. Back on serve, mid-set - not a set each, which is a later and much shorter moment. The other half of the trade the set-and-break rule opens: a position taken at the deep price is now in profit, and the market has snapped back towards him. This is a player who was losing and has turned it around, which is a different animal from one still going backwards, and the two should not carry the same price. Whether it is an exit or a fresh lay is not settled and the alert does not pretend otherwise. Both legs are logged, so the record will eventually say which side paid - see `python3 -m engine.report bands --rule fav_broke_back`. "At least one break" is a floor, not an equality: two or three breaks down and hauled back to on-serve is the same event, only bigger, and fires the same way. What matters is that the break count is square again - 4-4 after 0-4 counts, 2-4 after 0-4 does not, because he is still a break behind. Two things it deliberately will not fire on: a favourite who was never broken in the set, because holding serve is not a recovery; and a break-back in the deciding set, because that is a different situation from the second-set turnaround this is aimed at.

AngleThe bounce is in the price. Bank it here, or lay into it.

Medical timeout

Every one, whoever takes it and whatever the price. A treatment break is the clearest in-play information there is about what happens next, it is visible to anyone watching, and almost nobody is systematically recording them.

Won the first set, now being run over

A set up, and he has just lost four games in a row to trail by three or more in the second. He was the better player an hour ago, which is exactly why this reads as something having gone wrong rather than the stronger man pulling away. The strongest version of the two: he is still AHEAD in the match, so the games and set markets have not caught up and the match-winner price may not have moved at all.

Shipping games in the deciding set

Four games in a row lost in the deciding set, with the other man now four clear - 0-4, 1-5, 0-5. The "down 5-0 in the third" spot: the question is not whether he wins the match, it is whether he wins another game. In a deciding set both players have a set, so the won-a-set gate is already satisfied and what is left to filter is the score. Deciding sets finishing four games or more apart run at about 19 a day in the match record, which is the ceiling on this rule; without the lead gate a four-game run from 3-3 to 3-6 would fire too, and that is a set lost rather than a man who has stopped.