How Best to Determine Size of Trifecta Bet
 

Does anyone know of a rule-of-thumb for determining how to best size a trifecta bet based on pool size? Any books or articles discussing this subject? I would like to bet as much as a $50 trifecta (per combination) but I'm not sure how to best gauge whether $5, $10 or $20 would be more appropriate and under which circumstances (with respect to the pool size).


Has anybody already done the math?

Simple


It would depend on what the trifecta play consisted of


Longshots, bet less


Chalky, bet more



$50 would be a lot for something paying $1000 at smaller tracks

You have to figure out how much you are cutting your payout. If you have a $100,000 trifecta pool at a 22% take, that means they are paying out $78,000. If your $50 trifecta pays $40 for 1 that means there were 78000/40 or $1950 in winning tickets. To figure what the payoff would be if you only bet $20, take the 78000/1920(technically you should deduct the $30+the takeout from the pool size-but I am just trying to limit your work) and you get back $40.625, so in this instant you know exactly how much it cost you to hit it for $50 for $20. Plug in the numbers for the tracks you play, weigh the cost percentage wise relative to your profit margins and based off that info you can make the right decision. Obviously every trifecta pool is different but do this over 20 to 30 winning trifecta races and you will get a fairly good idea of what will work best for you and of course it will vary from track to track.

How are you determining the combinations on which you'll wager? Are you enumerating all possible combinations or doing something like the A/B/C method? If it's the former, you can actually solve the full kelly criterion taking into account the pool size. If the latter, you may be able to do some type of kelly estimate. I'd have to think more about a good way to the estimate, but it might be a fun little exercise.

The size is based on what you are willing to lose. No mystery, dont make harder than it already is.

I'm betting a 3 horse box. I also pre-bet (I play every tb track in North America every day) so Kelly wouldn't work for me unless I could somehow use the morning line. Probably wouldn't be too accurate tho.

$50 on a winning combination will not mess with the pool ceilings at the major tracks.
Races often have between $1,000 and $5,000 on winning combinations.

Small-circuit tracks could be an issue if your trifecta has a couple of the longest shots in big fields.

Look at the payout for a race, look at the trifecta pool for that race, take away about 25% for takeout, divide what is left after takeout by the $1 payout, and you should get an idea of how many $s were on the winning combination.

as far as like a Kelly type of thing, you probably want to simply use the minimums (50cents or $1) if you are betting a lot of races. If that works increase it by the min. increment.

you play every track and every race, a tri box?

Yes. Because I hit a lot of them. So I play them.


The more I play, the more I make. The more I bet, the more I make.


Hence my original question. How to best optimize my operation given the constraints of maintaining a reasonable risk/reward.


Ideally, I'd like to quantify it mathematically, like Kelly, but using pool size.

It is not difficult to make a spreadsheet that will calculate how various bet sizes affect payouts in various pool sizes. Then you can come up with a rule of thumb to bet X% of the estimated pool. If you are going to make a spreadsheet make sure you also add your losing bets into the calculation. (if you are boxing three horses you are buying five losing tickets.)

I have done it for myself but I am not going to tell you my conclusions because we likely have very different tolerances for how much our bet depresses the price, due to how many combinations we bet and our win percentage.

Let me clarify a bit.


I exclude turf, maidens and 2 year-olds in my play.


I play everything else.

At $5 to $50 unit per combo?

There is a WHALE in our midst. :eek::ThmbUp:

Yes. I started with a $150 bankroll and kept my risk at 2%, so my initial bets were 50¢. It grew fast. Inside of a week I was at $50.

So, you turned $150 into $15,000 in a week, and you're asking us for advice?....:lol: