Mike Mayo's Baby Bear: Street Whispers

Rutschow argues BGC will badly miss revenues generated from ELX Futures, an exchange backed by Wall Street to battle CME Group(CME) 's dominance over the trading of Treasury futures, but which has seen volumes shrink "to an unsustainably low level," according to Rotschow. He also believes new regulations discouraging the use of over the counter derivatives will put a big dent in BGC's business as a broker of those products. The call has worked out well so far, with BGC shares falling nearly 16% since July 26, while the Financial Select Sector SPDR ETF has gained more than 10%.

Though Mayo, at 49, is just nine years older than Rutschow, he sounded like a proud papa bear writing about the analyst in an email from Hong Kong.

"Perhaps I've rubbed off!" Mayo wrote, adding that Rutschow "was the only analyst to have a negative rating on now bankrupt MF Global, and he went negative not long after the CEO Jon Corzine attended our conference at CLSA. So--yes--he is independent."

-- Written by Dan Freed in New York.

Follow this writer on Twitter.