Pot-Limit Omaha: The Stack-to-Pot Ratio (SPR) Part II

Note: What follows is an edited excerpt from Advanced Pot-Limit Omaha Volume I: Small Ball and Short-Handed Play.

In my last column, we gave an introduction to the Stack-to-Pot Ratio, which is the ratio of the effective stacks to the current size of the pot. For example, if you have a $1,000 remaining stack and there is $100 in the pot, then your SPR is $1,000/$100 or simply 10. Alternatively, let’s say there’s $100 in the pot, you have a $1,000 stack (for an SPR of 10) and are heads up with an opponent who only has a $300 stack (for an SPR of $300/$100 or 3); in this case, the effective SPR is the SPR of the smaller stack — which is 3 — because the size of the smaller stack is all that you are playing for.

We also discussed high-SPR situations — when the SPR > 13 — as well as playing big-pot hands (the nut-straight with redraws, the overfull, top set when it is the nuts, the nut-flush, and big dominating draws) vs. playing small-pot hands (the bare nut-straight, middle set, bare top-two pair, etcetera) in these situations.

But a lot of times the effective SPR won’t be that high, either because there was either one raise or multiple raises before the flop, or because you are playing with shorter stacks to begin with. And when the SPR is less than or equal to 4 — a low SPR situation — you are in shove-or-fold territory. That is, if you face a bet and the SPR ≤ 4, then you should generally shove all-in if you contest the pot at all.

Small Pot/Low SPR Hands

The bare nut-straight
The underfull
Middle or bottom set
Undertrips (i.e. 8-7-6-5 on A-7-7 flop)
The second-nut flush
Big non-nut wraps

Low SPR Situations (SPR ≤ 4) and Ultra-Low SPR Situations (SPR ≤ 1)

Let’s say there’s $1,000 in the pot on the flop and everybody has $1,000 stacks, for an SPR of 1. You are last to act, the first player leads out with an all-in bet for $1,000, and everybody else folds to you. In this situation, you can’t fold hands like middle set, the underfull, undertrips, top two-pair, the bare nut-straight with no redraw, or the second-nut flush, because there are a lot more hands you can beat for one bet in a low-SPR situation than you can beat for three bets in a high-SPR situation; hands you can beat for one bet in a low-SPR situation might include hands such as one pair (like A-A-x-x), a draw, or a smaller flush.

Moreover, if your SPR is in the 1-to-4 range, you should raise and commit your stack when facing a bet when holding a small-pot hand like the bare nut-straight, middle or bottom set, top two-pair, a weaker wrap like 9-8-6-5 on a T-7-2 board, undertrips, something like K-K with the king-high flush draw on a J-7-2 board, or even top pair with redraws (something like T-9-8-7 on a T-5-2 board, especially with a flush draw to go with it) — hands that you should rarely (if ever) raise with when the effective SPR is high (SPR > 13).

The key is that when the SPR is low — when the pot is already big compared to the effective stack size — the range of hands you should be willing to commit with on the flop will widen dramatically. In fact, when the SPR gets down to 1 or less — ultra-low SPR territory — you almost can’t fold if you catch any piece of the flop whatsoever, especially as the SPR dips lower and lower.

Note that you only need 33.3 percent equity to justify an all-in confrontation with an SPR of 1, and only 25 percent equity when the SPR is down to 0.5. For this reason, I classify an ultra-low SPR as pot-odds territory, as you are playing essentially for pot odds.

That said, the gist of it is that the deeper the stacks and the higher the SPR, the bigger a mistake it is to commit to small-favorite/big-dog hands. Meanwhile, the shorter the stacks and the lower the SPR, the more aggressive you should be with the small-favorite/big-dog hands, and the more willing you should be to commit with some weaker holdings (such as undertrips or one pair) as well.

PLO Tip: The deeper the stacks and the higher the SPR, the bigger a mistake it is to commit your stack to the small pot (small-favorite/big-dog) hands such as a bare nut-straight, middle or bottom set, bare two-pair, or undertrips

PLO Tip: In a low SPR situation (SPR ≤ 4), you should generally shove all-in if you contest the pot at all.

PLO Tip: In ultra-low SPR situations (SPR ≤ 1), you are virtually pot-committed if you catch any piece of the flop. ♠

Jeff Hwang is a gaming industry consultant and author of Pot-Limit Omaha Poker: The Big Play Strategy and the three-volume Advanced Pot-Limit Omaha series.