What does equity mean on the bubble
Bubble equity refers to your expected monetary value (not chip value) at the exact moment before the bubble bursts. In other words: given everyone's stacks and the remaining prizes, how much money do you receive on average if we stop the tournament right here? That is your ICM equity. It's what a fair deal would give you — and by extension, it's what your push/fold decisions are maximizing.
The difference from chip equity
If you have 30% of the chips on the bubble, you do not have 30% of the total prize pool. You probably have less. For example, in a 4-handed bubble with stacks of 12/14/9/8 BB and payouts of 100/60/40/0, the player with 12 BB (30% of the chips) has roughly 30% of the pool in ChipEV, but only about 27% in ICM. Why? Because those 12 BB cannot "buy" more than one first-place prize, and the marginal probability of doubling up and winning is less than twice the probability of maintaining the current stack.
Step by step: how to calculate it
The Malmuth-Harville algorithm is recursive:
1. **P(player i finishes 1st)** = stack_i / sum(stacks). 2. For each player j who could finish 1st other than i, calculate **P(j finishes 1st) × P(i finishes 2nd given j finished 1st)** = (stack_j / total) × (stack_i / (total - stack_j)). 3. Repeat for 3rd, 4th… down to the last paid spot. 4. **EV(i) = Σ prize_k × P(i finishes in position k)**.
Doing this by hand for 3 players is manageable. For 5+ it becomes unworkable fast — which is why tools that automate it exist, like our free ICM calculator that supports up to 9 players.
Example: 4-handed bubble
Stacks: 12000, 14000, 9000, 8000. Payouts: 100, 60, 40, 0.
P(Player 1 finishes 1st) = 12/43 ≈ 27.9%. P(P1 finishes 2nd) = sum over the other three of [P(other finishes 1st) × stack_1 / (total - stack_other)]. And so on for 3rd.
The resulting ICM equity: - P1 (12k): ~$28.4 - P2 (14k): ~$32.1 - P3 (9k): ~$22.0 - P4 (8k): ~$17.5
Total = 100. The chip leader (P2) has 32.6% of the chips but ~32% of the pool — nearly proportional because the stacks are relatively close. In bubbles with a severely short-stacked player, the gap between ICM and ChipEV explodes.
Why it matters for your decisions
Knowing your ICM equity tells you **how much your next decision is worth**. If you call a push and lose, how much $EV do you lose? If you call and win, how much do you gain? The asymmetry between those two numbers is what defines your optimal calling range. On the bubble that asymmetry is enormous: you lose more $ by busting than you gain by doubling up. That's why regulars fold spots that would be mathematically +ChipEV but -$EV.
Calculate your spot in 30 seconds
If you want to see the ICM equity for your next bubble spot, you don't need to work through the math by hand. At /herramientas/calculadora-icm you'll find two tabs: Push/Fold to solve jam decisions, and Chip Chop to split the prize pool in a deal. No registration, no download, in Spanish.