they're not insolvent I wish everyone would stop going on about this. How could you actually fail that hard? They make more than half a percent on many of their transactions. They have a workable business model (when it works - it works!) If they genuinely don't have the cash I have no idea how they could have lost it.
I can think of at least five ways:
1. They were hacked and tons of their bitcoins were stolen.
2. The police seized a large chunk of their assets as part of crackdown on criminal use of bitcoins.
3. They wasted a fortune buying bitcoins at 10-20% above market.
4. They sold the clients' bitcoins at 100 USD to invest, price rose to 700 and they could not buy them back.
5. They reformatted the hard drive that had the only copy of their private keys.
And there are surely many more. The imagination of incompetent managers is amazing.