Holding company can have different non-banking subsidiaries.
WMI was more than 100 years old and they have 100s of non-banking subs like A.H.Hamson and co of $10B worth,they acquired.Acd....WM Citation,WMMRP..etc.
A bank can't file for a bankruptcy, it is the holding company that needs to file as far as know.
Due to contract law,some assets can't be sold during ch 11,it could take years as i read,in our case i think thats what happened and at the same time other issues like litigations,claims reconcilation and processing disputed claims like Dime and WMB Nholders false claims in more than $3 Billion.
JMO.