It's sort of true , banks are insured and unless you are below that insured amount or have it in an account with different criteria to a normal bank account you can lose out.
In Europe a standard bank account will guarantee up to €100k so if you have €99k in an account and the bank goes bankrupt you will get your €99k back but if you have €299k in that account you may only get €100k back depending on the overall situation of the bankruptcy.