In August 2010, we began reinvesting the proceeds from all securities that matured or were redeemed in longer-term Treasury securities, so as to keep the size of our securities holdings roughly constant. Around the same time, we began to signal to financial markets that we were considering providing additional monetary policy accommodation by conducting further asset purchases.
And in early November, we announced a plan to purchase an additional $ billion in longer-term Treasury securities by the middle of this year. All these purchases are settled through the banking system, with the result that depository institutions now hold a very high level of reserve balances with the Federal Reserve.