Chicago's unfunded pension benefits continue to rise way above the national average for the top U.S. cities, growing from $20 billion in 2014 to over $37 billion in 2023.  The funding of pensions and OPEB has been a financial and poltical problem for years in Chicago, with no end in sight. 

Unfunded pension benefits represents the total amount of pension liabilities for which the government does not have assets to pay benefits. It is calculated by summing the "net pension liabilities" and "net pension assets" of every plan for which that government is responsible, taking into account its share of multiple employer plans. This data is collected from each city's Annual Comprehensive Financial Report, as well as pension plan financial and actuarial reports.

Pension liabilities are determined through a calculation known as "discounting," which converts the future value of benefit payments into present-day dollars. The size of the present value of the liability depends heavily on the 'discount rate,' which is the interest rate that is assumed in the cost to fund the benefit payments.