[mseebach]

They don't "get deleted". When a bank manages your stock holdings, it's actually a different part of the business from the bank that you deposit cash into. All they do is hold in their computer systems (for a fee) the document that certifies that you own a piece of stock in company X. Just like you don't lose your stored stuff if a self storage business goes bankrupt (they or their creditors never have a claim on the stuff, the stuff is unequivocally yours), you don't lose your stock certificates if the bank goes bankrupt.

[sonnhy]

Thanks for clarification.