EXHIBIT 99.1

Immediately

Mark Furlong (414) 765-8052
Don Wilson (414) 765-8043

MARSHALL & ILSLEY CORPORATION
ANNOUNCES FIRST QUARTER RESULTS

Milwaukee, Wis. - April 11, 2003 - Marshall & Ilsley Corporation (NYSE: MI) today reported 2003 first quarter adjusted earnings of $0.57 per diluted share, or $129.5 million, as compared to $0.53 per diluted share, or $115.6 million, in the first quarter of 2002. First quarter adjusted earnings per share increased 7.5 percent over the same period in 2002. Earnings for the first quarter in 2003 were $0.56 per diluted share, or $128.0 million. First quarter earnings per share increased 5.7 percent over the first quarter of 2002. First quarter 2003 adjusted results exclude $0.01 per share in acquisition-related transition expenses.

Return on average assets based on adjusted income for the first quarter was 1.61 percent as compared to 1.72 percent for the same period in 2002. Return on equity based on adjusted income was 16.95 percent this quarter as compared to 18.04 percent for the first quarter of 2002.

Based on net income, return on average assets for the first quarter was 1.59 percent compared to 1.72 percent for the same period in 2002. Based on net income, return on equity was 16.75 percent this quarter as compared to 18.04 percent for the first quarter of 2002.

The Corporation's provision for loan and lease losses was $25.7 million in the first quarter, versus $15.2 million in the same period last year. Net charge-offs for the period were $25.8 million, or 0.44 percent of total average loans and leases outstanding this quarter, and $11.2 million a year ago or 0.23 percent of total average loans and leases. Included in the charge-offs for this quarter was $19.0 million related to the carrying value of lease obligations for airplanes leased to Midwest Express Airlines, Inc., the principal subsidiary of Midwest Express Holdings, Inc. At March 31, 2003 and 2002, the allowance for loan and lease losses was 1.40 percent of total loans and leases. Nonperforming loans and leases were 0.88 percent of total loans and leases at March 31, 2003, and 0.84 percent at March 31, 2002.

Assets at March 31, 2003 were $33.2 billion, compared to $28.6 billion at the end of 2002. Book value per share was $13.89 at March 31, 2003, compared to $12.42 for the same date a year ago. Total loans and leases at quarter end were $24.2 billion, compared to $20.3 billion at March 31, 2002.

All per share information reflects the two-for-one stock split which was effective June 17, 2002.

Adjusted income results for the first quarter of 2003 provided in this press release exclude certain transactions which management believes should be excluded in order to have a clear understanding of the Corporation's financial results. These items, which are included in GAAP net income results but which are excluded from adjusted income results, are described in the reconciliation table at the end of this press release.

Marshall & Ilsley Corporation (NYSE: MI) is a diversified financial services corporation headquartered in Milwaukee, Wis., with $33.2 billion in assets. Founded in 1847, M&I Marshall & Ilsley Bank has the largest banking presence in Wisconsin with 208 offices throughout the state. In addition, M&I has 25 locations throughout Arizona; 10 offices in metropolitan Minneapolis/St. Paul, Minn.; and, locations in Duluth Minn.; Las Vegas, Nev.; and Naples, Fla. M&I's Southwest Bank affiliate has six offices in the St. Louis area, and one office in Belleville, Ill. Metavante Corporation, Marshall & Ilsley Corporation's wholly owned technology subsidiary, is a leading financial services enabler - providing virtually all of the technology an organization needs to offer financial services. M&I also provides trust and investment management, equipment leasing, mortgage banking, asset-based lending, financial planning, investments and insurance services from offices throughout the country and on the Internet (www.mibank.com or www.micorp.com). M&I's customer-based approach, internal growth and strategic acquisitions have made M&I a nationally recognized leader in the financial services industry.

###

This press release contains forward-looking statements concerning M&I's future operations and financial results. Such statements are subject to important factors that could cause M&I's actual results to differ materially from those anticipated by the forward-looking statements. These factors include (i) the factors identified in M&I's Annual Report on Form 10-K for the year ended December 31, 2002, under the heading "Forward-Looking Statements" which factors are incorporated herein by reference, and (ii) such other factors as may be described from time to time in M&I's SEC filings.

Note:

Marshall & Ilsley Corporation will hold a conference call at 11:00 a.m. central daylight time Friday, April 11, regarding first quarter earnings. For those interested in participating, please call 1-800-211-3767 and ask for M&I's quarterly earnings release conference call. If you are unable to join us at this time, a replay of the call will run through 5:00 p.m. central daylight time April 18, 2003, by calling 1-800-839-6713 and entering passcode 558 11 47 to listen.

Additional financial information to be referenced in the conference call can be found at www.micorp.com, Investor Relations, Presentations, 1^st Quarter 2003 Supplemental Financial Information, after 8:00 a.m. on April 11.

[Quarterly Statistical Data attached]

M&I Corporation Financial Information (unaudited)
		Three Months Ended
		March 31,		March 31,		Percent
		2003		2002		Change
	PER SHARE DATA (a)
	Diluted:
	Net Income	$0.56		$0.53		5.7	%
	Income as Adjusted (b)	0.57		0.53		7.5
	Basic:
	Net Income	0.57		0.55		3.6
	Income as Adjusted (b)	0.57		0.55		3.6
	Dividend Declared	0.160		0.145		10.3
	Book Value	13.89		12.42		11.8
	Diluted Shares Outstanding (millions)	227.8		219.5		3.8
	INCOME STATEMENT ($millions)
	Net Interest Income (FTE)	$272.5		$248.3		9.7	%
	Provision for Loan and Lease Losses	25.7		15.2		69.1
	Data Processing Services:
	e-Finance	40.2		33.8		18.9
	Financial Technology Solutions	116.9		111.2		5.1
		______________		_______________
	Total Data Processing Services	157.1		145.0		8.3
	Item Processing	10.3		10.3		0.0
	Trust Services	30.0		31.0		-3.2
	Service Charge on Deposits	26.2		25.6		2.3
	Mortgage Banking	17.5		9.4		86.2
	Net Investment Securities Gains (Losses)	1.6		(0.7)		n.m.
	All Other	47.7		38.4		24.2
		______________		_______________
	Total Non-Interest Revenues	290.4		259.0		12.1
	Salaries and Employee Benefits	194.5		179.5		8.4
	Occupancy and Equipment	46.5		45.6		2.0
	Intangible Amortization	6.9		4.3		60.5
	Other	85.2		84.2		1.2
		______________		_______________
	Total Non-Interest Expenses	333.1		313.6		6.2
	Tax Equivalent Adjustment	8.0		8.0		0.0
		______________		_______________
	Pre-Tax Earnings	196.1		170.5		15.0
	Income Taxes	66.6		54.9		21.3
		______________		_______________
	Income as Adjusted (b)	129.5		115.6		12.0
		==============		===============
	Adjustments (b)	(1.5)		0.0		n.m.
		______________		_______________
	Net Income	$128.0		$115.6		10.7	%
		==============		===============
	KEY RATIOS
	Net Interest Margin(FTE) / Avg. Earning Assets	3.79	%	4.09	%	-7.3	%
	Interest Spread (FTE)	3.46		3.66		-5.5
	Efficiency Ratio	59.6		61.8		-3.6
	Efficiency Ratio without Metavante	48.5		50.7		-4.3
	Return on Assets	1.59		1.72		-7.6
	Return on Equity	16.75		18.04		-7.2
	Return on Assets - Income as Adjusted (b)	1.61		1.72		-6.4
	Return on Equity - Income as Adjusted (b)	16.95		18.04		-6.0
	Equity / Assets (End of Period)	9.41		9.53		-1.3
	Notes:   (a) Prior periods have been restated for the 2 for 1 stock split effective 6-17-02.               (b) See reconciliation of Income as Adjusted to Net Income.
M&I Corporation Financial Information (unaudited)
		As of
		March 31,		March 31,		Percent
	ASSETS ($millions)	2003		2002		Change
	Cash & Due From Banks	$958		$714		34.2	%
	Trading Securities	22		7		214.3
	Short - Term Investments	274		1,229		-77.7
	Investment Securities	5,278		4,240		24.5
	Loans and Leases:
	Commercial Loans & Leases	7,399		6,517		13.5
	Commercial Real Estate	7,716		6,078		26.9
	Residential Real Estate	2,818		2,497		12.9
	Home Equity Loans & Lines	4,118		3,517		17.1
	Personal Loans and Leases	2,149		1,676		28.2
		______________		_______________
	Total Loans and Leases	24,200		20,285		19.3
	Reserve for Loan & Leases Losses	(338)		(284)		19.0
	Premises and Equipment, net	439		417		5.3
	Goodwill and Intangibles	1,094		731		49.7
	Other Assets	1,322		1,221		8.3
		______________		_______________
	Total Assets	$33,249		$28,560		16.4	%
		==============		===============
	LIABILITIES & SHAREHOLDERS' EQUITY ($millions)
	Deposits:
	Noninterest Bearing	$4,278		$3,382		26.5	%
	Bank Issued Interest Bearing Activity	10,138		8,851		14.5
	Bank Issued Time	3,483		3,562		-2.2
		______________		_______________
	Total Bank Issued Deposits	17,899		15,795		13.3
	Wholesale Deposits	3,427		2,034		68.5
		______________		_______________
	Total Deposits	21,326		17,829		19.6
	Short - Term Borrowings	5,511		5,609		-1.7
	Long - Term Borrowings	2,272		1,523		49.2
	Other Liabilities	1,011		876		15.4
	Shareholders' Equity	3,129		2,723		14.9
		______________		_______________
	Total Liabilities & Shareholders' Equity	$33,249		$28,560		16.4	%
		==============		===============
		Three Months Ended
		March 31,		March 31,		Percent
		2003		2002		Change
	AVERAGE ASSETS ($millions)
	Cash & Due From Banks	$764		$650		17.5	%
	Trading Securities	18		10		80.0
	Short - Term Investments	257		1,086		-76.3
	Investment Securities	5,081		4,162		22.1
	Loans and Leases:
	Commercial Loans & Leases	7,221		6,258		15.4
	Commercial Real Estate	7,611		5,853		30.0
	Residential Real Estate	2,798		2,477		13.0
	Home Equity Loans and Lines	4,048		3,176		27.5
	Personal Loans and Leases	2,222		1,687		31.7
		______________		_______________
	Total Loans and Leases	23,900		19,451		22.9
	Reserve for Loan & Leases Losses	(345)		(280)		23.2
	Premises and Equipment, net	444		400		11.0
	Goodwill and Intangibles	1,089		635		71.5
	Other Assets	1,427		1,229		16.1
		______________		_______________
	Total Assets	$32,635		$27,343		19.4	%
		==============		===============
	AVG LIABILITIES & SHAREHOLDERS' EQUITY ($millions)
	Deposits:
	Noninterest Bearing	$3,860		$3,184		21.2	%
	Bank Issued Interest Bearing Activity	10,037		8,532		17.6
	Bank Issued Time	3,567		3,532		1.0
		______________		_______________
	Total Bank Issued Deposits	17,464		15,248		14.5
	Wholesale Deposits	3,683		1,784		106.4
		______________		_______________
	Total Deposits	21,147		17,032		24.2
	Short - Term Borrowings	3,610		4,474		-19.3
	Long - Term Borrowings	3,698		2,428		52.3
	Other Liabilities	1,080		810		33.3
	Shareholders' Equity	3,100		2,599		19.3
		______________		_______________
	Total Liabilities & Shareholders' Equity	$32,635		$27,343		19.4	%
		=============		===============
M&I Corporation Financial Information (unaudited)
		Three Months Ended
		March 31,		March 31,		Percent
		2003		2002		Change
	CREDIT QUALITY (a)
	Net Charge-Offs (Recoveries) ($millions)	$25.8		$11.2		130.4	%
	Net Charge-Offs (Recoveries) / Average Loans & Leases	0.44	%	0.23	%
	Loan and Lease Loss Reserve ($millions)	$338.3		$284.2		19.0	%
	Loan and Lease Loss Reserve / Period-End Loans & Leases	1.40	%	1.40	%
	Non-Performing Loans & Leases (NPL)($millions)	$212.1		$170.3		24.5	%
	NPL's / Period-End Loans & Leases	0.88	%	0.84	%
	Loan and Lease Loss Reserve / Non-Performing Loans & Leases	159	%	167	%
	MARGIN ANALYSIS (b)
	Loans and Leases:
	Commercial Loans & Leases	4.70	%	5.40	%
	Commercial Real Estate	5.96		6.85
	Residential Real Estate	6.39		7.21
	Home Equity Loans and Lines	5.96		6.93
	Personal Loans and Leases	5.76		7.21
		______________		_______________
	Total Loans and Leases	5.61		6.47
	Investment Securities	5.52		7.32
	Trading Securities	1.48		2.58
	Short - Term Investments	1.16		1.66
		______________		_______________
	Interest Income(FTE) / Avg. Interest Earning Assets	5.56	%	6.40	%
		==============		===============
	Interest Bearing Deposits:
	Bank Issued Interest Bearing Activity	0.90	%	1.30	%
	Bank Issued Time	2.70		3.74
		______________		_______________
	Total Bank Issued Deposits	1.37		2.01
	Wholesale Deposits	1.84		2.50
		______________		_______________
	Total Interest Bearing Deposits	1.47		2.08
	Short - Term Borrowings	2.48		3.52
	Long - Term Borrowings	4.63		5.07
		______________		_______________
	Interest Expense / Avg. Interest Bearing Liabilities	2.10	%	2.74	%
		==============		===============
	Net Interest Margin(FTE) / Avg. Earning Assets	3.79	%	4.09	%
		==============		===============
	Interest Spread (FTE)	3.46	%	3.66	%
		==============		===============
	Notes:    (a) Includes Loans past due 90 days or more                (b) Based on average balances excluding fair value adjustments for available for sale securities.
	Reconciliation of Income as Adjusted to Net Income
	Income as Adjusted	$129.5		$115.6
	Acquisition and Transition Related
	Charges - Metavante	(1.5)		0.0
		______________		_______________
	Net Income	$128.0		$115.6
		==============		==============
	METAVANTE CORPORATION METRICS (000's)
	e-Finance
	Bill Payment Transactions	20,406		9,919		105.7	%
	Bill Payment Active Consumers	918		405		126.7
	Consumer eBanking Users	536		470		14.1
	Financial Technology
	EFT Transactions Switched/Routed	281,019		220,542		27.4
	Debit Transactions Authorized/Settled	168,307		138,286		21.7
	Financial Technology Transactions	1,810,537		1,546,564		17.1