If one industry can claim to have the most riding on states participating in the health law's Medicaid expansion, it's near-certainly hospitals. They have nearly $40 billion riding on whether states sign up or not. Hospitals regularly get stuck with bills that the uninsured cannot afford to pay. Every year, the American Hospital Association adds all those bills up to calculate the total amount of uncompensated care that its members provide. Every year, the number gets bigger and bigger, hitting $39.3 billion in 2010.