"Allegations are arising that the audit of PFG segregated accounts following the MFG collapse took place without the auditor's looking at actual bank statements to confirm that the money alleged to be sitting in the bank accounts matched what the records indicated."
That is not the way brokers work.
If you trade futures, your margins don't sit in a bank account with your name on it! The only thing that is "segregated" are your account records held by the broker.
Margins are pooled. The required margins are paid to the Central Clearer (CME in this case) on an agregrate basis. Any surplus to that requirement is invested by the broker in their own name.
This work well as long as the broker invests the cash wisely. Unfortunately, with a zero Fed Funds rate, some US brokers invested their cash resources (capital and money not deposited with CME) in some risky asset to improve their profits.
You can guess the rest. (MFGlobal blew their client's money investing in European sovereign debt. I haven't heard how PFG blew it.)
All an auditor can do is validate the client account records and ensure that the broker holds sufficient assets to cover all clients cash holdings.
"Are (other) collapses imminent?"
I have been in the market 30 years. This sort of thing happens all the time, particularly when investment asset values are falling. If there wasn't another major broker collapse in the US before the end of the year, I would be surprised.
