The declining values of office buildings across the country in the aftermath of the COVID-19 pandemic could significantly change how major cities and other localities raise revenue and provide public services. This paper describes the mechanics of commercial property tax collection and uses Annual Comprehensive Financial Report data to show how and why commercial property tax collections vary across 47 cities. It then combines these data with forecasts of office building values for the 13 cities in the largest office markets in the United States to forecast how much revenue cities might lose over the next decade compared with pre-pandemic trends. Depending on the assumptions in the forecast, the median projected decline in commercial property tax revenue by 2031 ranged from 2.5 to 3.5 or from 0.9 to 3.2 percent of total city revenue. However, the severity of the shortfall was far larger in some cities, and some cities saw large swings in the projected shortfall under the two different forecasts. These data highlight the major questions policymakers should ask when assessing the specific future of their local budgets.