Section 203.4 - Financial institution eligibility for designation as a TT&L depositary(a) To be designated as a TT&L depositary, a financial institution must be insured as a national banking association, state bank, savings bank, savings association, building and loan, homestead association, Federal home loan bank, credit union, trust company, or a U.S. branch of a foreign banking corporation, the establishment of which has been approved by the Comptroller of the Currency.(b) A financial institution must possess the authority to pledge collateral to secure TT&L account balances, a TIP main account balance, an SDI account balance, or a no account balance as applicable.(c) In order to be designated as a TT&L depositary for the purposes of processing Federal tax deposits through PATAX, a financial institution must possess under its charter either general or specific authority permitting the maintenance of the TT&L account, the balance of which is payable on demand without previous notice of intended withdrawal. In addition, investor depositaries and retainer depositaries must possess either general or specific authority permitting the maintenance of a TIP main account 27 balance or an SDI account balance. Investor, retainer, and collector depositaries that accept term investments must possess either general or specific authority permitting the maintenance of a TIO account balance. In the case of investor and retainer depositaries maintaining a TIP main account balance or an SDI account balance, the authority must perm it the maintenance of a TIP main account balance or an SDI account balance which is payable on demand without previous notice of intended withdrawal.