The Mystery of Banking by Murray N. Rothbard (pg. 159)

Here when the Fed purchases a bond directly from a bank, there is no initial increase in demand deposits, or in total bank assets or liabilities. But the key point is that Citibank’s reserves have, once again, increased by the $1,000,000 of the Fed’s open market purchases, and the banking system can readily pyramid a multiple amount of loans and deposits on top of the new reserves.