ICM (Independent Chip Model)
A model for converting tournament chip stacks into real-money equity.
In a tournament, chips are not money. The first chip you win is worth more than the last (because each chip moves you closer to the min-cash). ICM converts chip stacks into expected prize-pool share by simulating finishing positions.
ICM matters most near the bubble and at final tables. A short stack on the bubble can correctly fold hands that would be easy chip-EV calls — because busting before the money is much more expensive than doubling up.
Practical heuristic: as the field shrinks and pay jumps grow, your calling ranges should tighten and your shoving ranges should widen (especially against medium stacks who can't call without ICM pressure of their own).