Exhibit 12.1

Northern Trust Corporation

Ratio of Earnings to Fixed Charges

(Dollars in Millions)

	Six Months Ended 6/30/2017
			Fiscal Year Ended December 31,
			2016		2015		2014		2013		2012
EXCLUDING INTEREST ON DEPOSITS:
Fixed Charges
Interest Expense (Excluding Interest on Deposits)	$	63.9	$	98.5	$	79.6	$	99.7	$	119.0	$	140.7
Estimated Interest Component of Rental Expense		15.2		28.4		27.4		29.1		27.7		30.4
Total Fixed Charges	$	79.1	$	126.9	$	107.0	$	128.8	$	146.7	$	171.1
Income:
Income Before Income Taxes	$	781.7	$	1,517.1	$	1,465.0	$	1,190.2	$	1,075.5	$	992.3
Fixed Charges		79.1		126.9		107.0		128.8		146.7		171.1
Earnings, as Defined	$	860.8	$	1,644.0	$	1,572.0	$	1,319.0	$	1,222.2	$	1,163.4
Ratio of Earnings to Fixed Charges		10.89		12.95		14.69		10.24		8.33		6.80
INCLUDING INTEREST ON DEPOSITS:
Fixed Charges
Interest Expense (Including Interest on Deposits)	$	132.5	$	182.0	$	153.9	$	181.4	$	222.4	$	297.4
Estimated Interest Component of Rental Expense		15.2		28.4		27.4		29.1		27.7		30.4
Total Fixed Charges	$	147.7	$	210.4	$	181.3	$	210.5	$	250.1	$	327.8
Income:
Income Before Income Taxes	$	781.7	$	1,517.1	$	1,465.0	$	1,190.2	$	1,075.5	$	992.3
Fixed Charges		147.7		210.4		181.3		210.5		250.1		327.8
Earnings, as Defined	$	929.4	$	1,727.5	$	1,646.3	$	1,400.7	$	1,325.6	$	1,320.1
Ratio of Earnings to Fixed Charges		6.29		8.21		9.08		6.65		5.30		4.03

Northern Trust Corporation

Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends

(Dollars in Millions)

	Six Months Ended
			Fiscal Year Ended December 31,
	6/30/2017		2016		2015		2014		2013		2012
EXCLUDING INTEREST ON DEPOSITS:
Fixed Charges
Interest Expense (Excluding Interest on Deposits)	$	63.9	$	98.5	$	79.6	$	99.7	$	119.0	$	140.7
Estimated Interest Component of Rental Expense		15.2		28.4		27.4		29.1		27.7		30.4
Pre-Tax Earnings Required for Preferred Dividends		42.7		37.6		37.6		15.2		—		—
Total Fixed Charges and Preferred Stock Dividend Requirements	$	121.8	$	164.5	$	144.6	$	144.0	$	146.7	$	171.1
Income:
Income Before Income Taxes	$	781.7	$	1,517.1	$	1,465.0	$	1,190.2	$	1,075.5	$	992.3
Fixed Charges and Preferred Stock Dividend Requirements		121.8		164.5		144.6		144.0		146.7		171.1
Earnings, as Defined	$	903.5	$	1,681.6	$	1,609.6	$	1,334.2	$	1,222.2	$	1,163.4
Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends		7.42		10.22		11.13		9.26		8.33		6.80
INCLUDING INTEREST ON DEPOSITS:
Fixed Charges
Interest Expense (Including Interest on Deposits)	$	132.5	$	182.0	$	153.9	$	181.4	$	222.4	$	297.4
Estimated Interest Component of Rental Expense		15.2		28.4		27.4		29.1		27.7		30.4
Pre-Tax Earnings Required for Preferred Dividends		42.7		37.6		37.6		15.2		—		—
Total Fixed Charges and Preferred Stock Dividend Requirements	$	190.4	$	248.0	$	218.9	$	225.7	$	250.1	$	327.8
Income:
Income Before Income Taxes	$	781.7	$	1,517.1	$	1,465.0	$	1,190.2	$	1,075.5	$	992.3
Fixed Charges and Preferred Stock Dividend Requirements		190.4		248.0		218.9		225.7		250.1		327.8
Earnings, as Defined	$	972.1	$	1,765.1	$	1,683.9	$	1,415.9	$	1,325.6	$	1,320.1
Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends		5.11		7.12		7.69		6.27		5.30		4.03