There is a relatively new betting phenomena in horse racing. There is deliberate toteboard manipulation by a small number of computer wagering syndicates. They go by the abbreviation CAW (computer assisted wagering). What they are doing is making a mockery of the game.
When CAW groups are "in" on a race, you can expect the following to happen:
1) A horse will be live as indicated in the multi-race will-pays.
2) Live runner is at higher odds for most of the betting than the will-pays would suggest.
3) Cancelation on "fake bets" made on other horses to buoy the odds of the live runner.
4) Large wagers come in on the live runner as the final horse loads.
5) Live runner plummets to its lowest odds just as the horses leave the gate.
6) Live runner runs a winning race.
There are a few troubling things here. While they are all connected, the reason they are problematic are independently different.
Late Odds Swing
This is the most frustrating thing to horseplayers but is actually the least problematic. We can tell what odds horses are likely to land by perusing the will-pays (assuming it is a race that is ending a multi-race sequence). Not every player references the will-pays so betting a horse at 15-1 as they load in the gate and see it win at 7-2 is extraordinarily disappointing. It's happening all the time (see some screen shots at the bottom of this article).
We know the CAW's have a live-time feed into the betting pools. This allows them to bet as the last horse loads (no video lag). But they are also heavily manipulating the odds we see throughout the betting. It's become predictable. If a horse is overbet in the will-pays and is dramatically higher on the board, you can assume there will be late money crushing it down. This is not someone seeing an overlay on the board and betting it. It is someone creating the illusion of a dead horse in order to dissuade superficial players from betting it. This is closely related to the late odds swing which can be predicted but it makes the game look cheap and unworthy of serious involvement.
Late odds swing along with the toteboard manipulation is a problem due to the accuracy of the live horse winning. In normal times, you could expect any kind of steam betting to be wrong 60% - 70% of the time. That means when you are on someone else you are getting a bump up in odds at the last minute. Your 2-1 shot at post goes off at 7-2. This would be great if your bump up runner wins. It doesn't. Not often. However, the steam horse appears to win at illogical rates. At some point there will be a serious study done to identify the actual win percentage. In lieu of that, my observation is they are right in the neighborhood of 70% - 80% of the time.
It's unclear how they are so accurate. If they have sophisticated algorithms that analyze shared data better than the rest of us, more power to them. I have no issue with that. That seems highly improbable. It feels like inside information. Given the myriad of tracks, riders, trainers, owners and connections involved in these situations, it's not likely this is a one-to-one disclosure of inside information. If I had to guess, it would be more of a sophisticated pipeline of information (with money changing hands) from barn to liaison to CAW team.
The how is for another day. The truth is the money that is controlling the odds is landing on the right horse too often and driving serious (honest) players out of the game. One wonders how much handle there is if you extract all CAW money from the data. The tracks have made a deal with the devil. They are working on thin margins and the handle from CAW's is needed to keep operations running. Unfortunately for bettors, where the money comes from is not a concern of the tracks. They are able to take their cut no matter who the winners and losers are. If tracks were on the hook to pay winners with fixed odds, they would have long ego eradicated this activity just as they do in casinos.
Here are a few examples of accurate late money. I have dozens of these screen shots.