It started out as a routine workday at the buttoned-up offices of Dream Exchange, a fledgling stock exchange outside Chicago. Then Charlie Bills showed up. In flip-flops. 

Bills was there last summer to see Joe Cecala, the company’s founder and CEO. He took a seat on the couch outside the executive office and was told to wait. To those around him, Bills stuck out, and not just because he was a stranger with his toes out.