Seven banking and credit union associations have sent a letter to the Office of the Comptroller of the Currency (OCC), the regulator of national banks in the U.S., spelling out the dangers of the OCC approving a pending bank charter that would allow a national bank to accept and hold deposits that lack federal deposit insurance. The lack of federal deposit insurance triggered the bank runs and banks collapses that played a key role in ushering in the Great Depression. (More on that in a moment.)