What Will Wall Street Do without Michael Bloomberg?

When Michael Bloomberg steps down as New York City mayor at the end of the year, few constituencies will miss him as much as Wall Street.

For 12 years, Bloomberg has gone from tireless cheerleader for the financial services industry after the September 11 attacks, to its strident defender against Occupy Wall Street protests over economic inequality and calls for higher taxes on the wealthy.

But now the business elite has reason to pause. An unabashed liberal, city official Bill de Blasio, is leading opinion polls to replace Bloomberg in the November 5 election while pounding a theme of "a tale of two cities" - one rich and one poor.