But the demographic challenges of the Big Orange and the Windy City pale compared to those faced by many cities in the old industrial Rust Belt, which have either lost population or posted only weak increases.

FORBES: America's Fastest- and Slowest-Growing Cities

Although, investment banks post reports on the net, Mr Yearsley argues that the information available to private investors is a pale shadow of that which reaches the desks of City professionals.

BBC: Q & A The role of the City analyst