Mayor Rahm Emanuel and City Budget Director Alex Holt returned to a familiar refrain on the Monday morning property tax bills were due: Chicago’s booming economy played a key role in helping to haul the city out of its financial mess. At a City Club event featuring Holt, Mayor Emanuel again touted the city’s overall fiscal picture–educational investments, corporate relocations, foreign investment, and tourism–similar to an address he gave to municipal bond analysts in May.