What Is ICM in Poker?

ICM stands for Independent Chip Model. In poker tournaments, it converts every remaining stack and the payout structure into expected prize-pool equity. Unlike a cash-game chip, a tournament chip does not have a fixed cash value.

In fact, the value of a tournament chip is variable. The value changes as a tournament progresses, but also each individual chip is worth less the more that you have.

How does ICM work? A worked example

ICM works out how likely each player is to finish in each place, using their share of the chips, and then multiplies those chances by the payouts. Say three players are left with 10,000 chips between them, and the prize pool pays 50%, 30% and 20%:

The chip leader has half the chips but only about 38% of the money. The short stack has a fifth of the chips but nearly 29% of the money, because 20% of the prize pool is locked in just for finishing third. That's why chips you win are worth less than chips you lose. You can try your own stacks in the ICM calculator.

Why does ICM matter so much to short stacks?

This is a big reason why understanding short stack strategy is so important. When you are short stacked is when your individual chips are worth the most. Don't be like many players that give up and gamble that value away - understand how to make optimal decisions to make the most of your stack at every stage of the game.

How does ICM change your strategy?

ICM also changes the nature of your strategy significantly. Busting a tournament becomes a lot more costly, so we are generally tighter compared to chip-EV strategies. However, there are also still opportunities to be more aggressive. For example, it's not just you that have this pressure. If you are a large covering stack, then you have the opportunity to apply huge pressure to smaller stacks, forcing them to fold more than they normally would.

Combining this with a strong understanding of fold equity opens up opportunities to get the maximum benefit based on the incentives of each hand.

Here's what that looks like in our solutions. On a 6-max bubble with five paid, the Button has 10bb and it folds to them. In ChipEV they shove about 39% of hands. When both blinds are short (8bb and 7bb), the Button shoves about 52% - the blinds can't afford to call. When both blinds are deep (21bb and 45bb), the Button shoves only about 32%, because now the Button is the one who can't afford to get called. Same seat, same stack - the blinds decide it. See the ICM bubble charts for the full ranges.

When does ICM matter most?

ICM pressure is sharpest right around the bubble and every pay jump after it, and it matters more the shorter your own stack is relative to what you'd win by surviving. Deep in the money with stacks still relatively even, chip-EV and ICM mostly agree; the gap widens exactly when the payout jumps get steep.