Most of the world’s urban mass transitsystems cannot cover operating costs, let alone capitalexpenses, through farebox revenues. On average, 25 percentof metro operating expenditures are not funded by fareboxincome. With limited public subsidies, as well as obstaclesto raising fares and political sensitivities to road usertaxes, metro systems have been increasingly pursuing incomefrom commercial activities connected with their operations.Metro systems earn commercial income, such as fromadvertising, naming rights, and especially real estateactivities, are making inroads in their operating deficits.Commercial revenue in some systems is nearing 20 percent offare revenue. Although reforms of transit financingstructures remain high on the policy agenda, a review ofancillary income streams of metro systems around the worldshows that a more entrepreneurial approach to tapping theircommercial potential can help them narrow their funding gap.