Shared cost agreements are contracts between governments defining how costs for jointly funded programs or projects will be divided. Infrastructure projects often involve federal, provincial, and municipal cost sharing—with typical splits like one-third each or 40% federal/33% provincial/27% municipal. Social programs may have provincial-municipal cost sharing. Agreements specify not just percentages but also what costs qualify, payment schedules, reporting requirements, and what happens if costs exceed estimates. Negotiating fair cost sharing is challenging when governments have different fiscal capacities and policy priorities. Cost-sharing formulas significantly affect which projects municipalities can afford to pursue.