On 21 December 2011 the bank instituted a programme of making low-interest loans with a term of three years (36 months) and 1% interest to European banks accepting loans from the portfolio of the banks as collateral. Loans totalling €489.2 bn (US$640 bn) were announced. The loans were not offered to European states, but government securities issued by European states would be acceptable collateral as would mortgage-backed securities and other commercial paper that can be demonstrated to be secure. The programme was announced on 8 December 2011 but observers were surprised by the volume of the loans made when it was implemented. Under its LTRO it loaned €489bn to 523 banks for an exceptionally long period of three years at a rate of just one percent. The by far biggest amount of €325bn was tapped by banks in Greece, Ireland, Italy and Spain. This way the ECB tried to make sure that banks have enough cash to pay off €200bn of their own maturing debts in the first three months of 2012, and at the same time keep operating and loaning to businesses so that a credit crunch does not choke off economic growth. It also hoped that banks would use some of the money to buy government bonds, effectively easing the debt crisis.