State and local governments in the U.S. have big debts in the form of pension promises to employees. These promises are like loans from workers that the government has to pay back when they retire. The researchers studied how these promises affect public finances and financial markets. They looked at the value of these promises, how different policies can change their value, and if bond markets react to them. Most state governments offer pension plans where the employer promises a payment to the employee when they retire. This creates a financial burden for taxpayers. When the worker retires, the state has to pay them. States manage pension funds to cover these payments.