Record high margin debt and short selling

Newspapers and yahoos point to the record high margin debt as showing the speculation in the markets. My guess is that short interest in stocks is still at record high or close to it. Regulation T says you can only short stocks in a margin account? Are brokerage firms and banks included in short interest reports?? Is John Doe using that much margin to buy stocks? Or is this a short squeeze on all the "smart money" being short stocks? And that showing up as the high borrowing on margin?