As of today, there was only one SEC filing for an "involuntary liquidation" due to a margin call. see: <A HREF="http://www.secinfo.com/$/SEC/Registrant.asp?CIK=899723" target="_new">http://www.secinfo.com/$/SEC/Registrant.asp?CIK=899723</A> (the Form 4 filing is at the bottom of the page)