The $93.5 billion in Treasury liabilities shows that the Treasury Department does not use private banks but rather uses the Fed directly.

http://en.wikipedia.org/wiki/Federal_Reserve_System#cite_note-91

The $93.5 billion in Treasury liabilities shows that the Treasury Department does not use private banks but rather uses the Fed directly (the lone exception to this rule is Treasury Tax and Loan because the government worries that pulling too much money out of the private banking system during tax time could be disruptive).