Here is a list of all the regulated collateral that the Fed is lending against

Lame brained journalists at Bloomberg.com like Mark Pittman, Bob Ivry and Alison Fitzgerald could have looked this up before they wrote their horribly irresponsible article on the Fed's lending.

Collarteral Margins Table.

Everything on that list is regulated collateral. Banks can pledge any of those things as collateral for loans.

Moreover, as Warren Mosler states:

"...the Fed asking for collateral from US member banks is ‘redundant’ in that FDIC/OCC regulation/supervision already requires all bank collateral be ‘bank legal’ and that required capital be sustained."