Pledged Assets	3 Months Ended
Mar. 31, 2012
Pledged Assets	7. Pledged Assets – Certain of Northern Trust’s subsidiaries, as required or permitted by law, pledge assets to secure public and trust deposits, repurchase agreements, Federal Home Loan Bank borrowings, and for other purposes. At March 31, 2012, $27.2 billion ($23.9 billion of government sponsored agency and other securities, $412.8 million of obligations of states and political subdivisions, and $2.9 billion of loans) were pledged. This compares to $27.9 billion ($21.5 billion of government sponsored agency and other securities, $460.2 million of obligations of states and political subdivisions, and $6.0 billion of loans) at December 31, 2011. Collateral required for these purposes totaled $4.2 billion and $4.8 billion on March 31, 2012 and December 31, 2011, respectively. Included in the total pledged assets at March 31, 2012 and December 31, 2011 were available for sale securities with a total fair value of $249.6 million and $1.2 billion, respectively, which were pledged as collateral for agreements to repurchase securities sold transactions. The secured parties to these transactions have the right to repledge or sell these securities. Northern Trust is permitted to repledge or sell collateral from agreements to resell securities purchased transactions. The total fair value of accepted collateral as of March 31, 2012 and December 31, 2011 was $280.9 million and $74.7 million, respectively. There was no repledged or sold collateral at March 31, 2012 or December 31, 2011. Deposits maintained to meet Federal Reserve Bank reserve requirements averaged $1.1 billion and $331.5 million for the three months ended March 31, 2012 and 2011, respectively.

7. Pledged Assets – Certain of Northern Trust’s subsidiaries, as required or permitted by law, pledge assets to secure public and trust deposits, repurchase agreements, Federal Home Loan Bank borrowings, and for other purposes. At March 31, 2012, $27.2 billion ($23.9 billion of government sponsored agency and other securities, $412.8 million of obligations of states and political subdivisions, and $2.9 billion of loans) were pledged. This compares to $27.9 billion ($21.5 billion of government sponsored agency and other securities, $460.2 million of obligations of states and political subdivisions, and $6.0 billion of loans) at December 31, 2011. Collateral required for these purposes totaled $4.2 billion and $4.8 billion on March 31, 2012 and December 31, 2011, respectively. Included in the total pledged assets at March 31, 2012 and December 31, 2011 were available for sale securities with a total fair value of $249.6 million and $1.2 billion, respectively, which were pledged as collateral for agreements to repurchase securities sold transactions. The secured parties to these transactions have the right to repledge or sell these securities.

Northern Trust is permitted to repledge or sell collateral from agreements to resell securities purchased transactions. The total fair value of accepted collateral as of March 31, 2012 and December 31, 2011 was $280.9 million and $74.7 million, respectively. There was no repledged or sold collateral at March 31, 2012 or December 31, 2011. Deposits maintained to meet Federal Reserve Bank reserve requirements averaged $1.1 billion and $331.5 million for the three months ended March 31, 2012 and 2011, respectively.