Here is WTS's financials (just talking about the US prop broker dealer) from 12-31-2011 from SEC.gov. They came up a few months late compared to when other firms data was posted.
http://www.sec.gov/Archives/edgar/vprr/12/9999999997-12-010053
The member's equity ($2.4 million) is about the smallest around for a prop firm. And they still won't disclose how much is actually the owners capital versus the trader's deposits, so this thing could be running 100% on trader deposits for all we know.
Another red flag is paragraph 10 in the notes.
"In February 2011 the Company received notice from its SRO self regulatory organization the CBOE Stock Exchange that the Company accepted capital contributions from some of its members that were not subject to the one year lock up period and should be treated as customer funds If finalized this would be considered violation of Exchange rules as the Company is approved only to trade for its own account The Company strongly believes it has not accepted customer funds and has responded accordingly The case remains pending."
If the firm is being run on trader deposits, and the CBOE hits them, or they incur large legal fees fighting it (and the class A owners don't feel like putting money in), then people may not be getting all their capital contributions back.
So make sure you ask extra questions before doing business with them to see if the compliance stuff is resolved and whose capital (owners or trader's) money they are using to run the firm.
Again, the US CBOE broker dealer is what I am referring to. Not sure what goes on out of the US.