This is what he said (watch the video after the jump):
"It's very strange for someone like me who watches money because individuals have been selling, companies are net selling, [...] insider selling and new offerings are swamping any buyback or any cash M&A activity since QE2 was announced. Pension funds, hedge funds don't really have that much new cash to invest. So [...] who's buying the stock that people are selling. It's QE2. Since QE2 the market's gone up. So what nobody's asking or what I'm asking is what happens when QE2 stops? If the only buyer is the Fed and the Fed stops buying, I don't know what's going to happen."
On where money is leaving:
"Well it's leaving Municipal bond funds primarily because of the losses. We've done the same analysis that Meredith Whitney has done and States and Municipalities have about a $200 billion annualized shortfall. If they can't make it up, you know they can't fire that many people to balance their budgets. How are they going to pay their debt service without Federal Government help. Maybe in June the Fed will start buying Municipal bonds like they're buying Treasury bonds now."
Read Biderman's follow up at Zero Hedge.