Exhibit 99.1

News Release	Marshall & Ilsley Corporation 770 North Water Street/Milwaukee, Wisconsin 53202
For release:	Immediately
For further information:	Mark Furlong, president M&I Marshall & Ilsley Bank,  (414) 765-8052
	Don Wilson, senior vice president, corporate treasurer, (414) 765-8043

MARSHALL & ILSLEY CORPORATION ANNOUNCES THIRD QUARTER RESULTS

John M. Presley to Join M&I October 18 as Chief Financial Officer

Milwaukee, Wis. – Oct. 13, 2004 – Marshall & Ilsley Corporation (NYSE: MI) today reported 2004 third quarter net income of $0.69 per diluted share, or $155.4 million, as compared to $0.61 per diluted share, or $140.3 million, in the third quarter of 2003. Third quarter net income per share increased 13.1 percent over the same period in 2003.

Net income for the nine months ended September 30, 2004 was $453.3 million, or $2.01 per diluted share, compared to $403.0 million, or $1.77 per diluted share, in the nine months ended September 30, 2003.  

Return on average assets based on net income for the third quarter was 1.63 percent, as compared to 1.66 percent for the same period in 2003.  Return on average equity based on net income was 17.58 percent this quarter as compared to 16.92 percent for the third quarter of 2003.  

The Corporation’s provision for loan and lease losses was $6.9 million in the third quarter of 2004, versus $7.9 million in the same period last year.  Net charge-offs for the period were $6.7 million, or 0.10 percent of total average loans and leases outstanding this quarter, and $7.9 million a year ago or 0.13 percent of total average loans and leases.  At September 30, 2004, the allowance for loan and lease losses was 1.27 percent of total loans and leases, compared to 1.41 percent a year earlier.  Nonperforming loans and leases were 0.51 percent of total loans and leases at September 30, 2004, and 0.76 percent at September 30, 2003.

Assets at September 30, 2004 were $39.0 billion, compared to $33.7 billion at September 30, 2003.  Book value per share was $16.19 at September 30, 2004, compared to $14.84 for the same date a year ago.  Total loans and leases were $28.1 billion, compared to $24.6 billion at September 30, 2003.

John M. Presley to Join M&I October 18 as Chief Financial Officer

The Corporation has also announced John M. Presley will join Marshall & Ilsley Corporation as Senior Vice President and Chief Financial Officer on Monday, October 18.  Presley’s appointment was announced in August of this year.  He succeeds Mark F. Furlong who became President of M&I Marshall & Ilsley Bank on July 1, 2004.  Presley previously served as Chief Financial Officer of National Commerce Financial Corporation in Memphis, Tennessee.

Marshall & Ilsley Corporation (NYSE: MI) is a diversified financial services corporation headquartered in Milwaukee, Wis., with $39.0 billion in assets. Founded in 1847, M&I Marshall & Ilsley Bank has the largest banking presence in Wisconsin with 197 offices throughout the state. In addition, M&I has 32 locations throughout Arizona; 11 offices in metropolitan Minneapolis/St. Paul, Minn.; and, locations in Duluth, Minn.; Las Vegas, Nev.; and, Naples and Bonita Springs, 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, provides 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.

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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, 2003 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 Wednesday, October 13, regarding third quarter earnings.  For those interested in listening, please call 1-800-243-6403 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 October 20, 5:00 p.m. central daylight time by calling 1-800-839-6713 and entering passcode 666 28 25 to listen.

Supplemental financial information referenced in the conference call can be found at www.micorp.com, Investor Relations, after 8:00 a.m. on October 13.

M&I  Corporation
Financial Information
(unaudited)
	Three Months Ended						Nine Months Ended
	September 30,		September 30,		Percent		September 30,		September 30,		Percent
	2004		2003		Change		2004		2003		Change
PER SHARE DATA
Diluted:
Net  Income	$0.69		$0.61		13.1	%	$2.01		$1.77		13.6	%
Income as Adjusted (a)	0.69		0.61		13.1		2.01		1.77		13.6
Basic:
Net  Income	0.70		0.62		12.9		2.04		1.78		14.6
Income as Adjusted (a)	0.70		0.62		12.9		2.04		1.79		14.0
Dividend Declared	0.210		0.180		16.7		0.600		0.520		15.4
Book Value	16.19		14.84		9.1		16.19		14.84		9.1
Shares  Outstanding (millions):
Average - Diluted	226.2		228.9		-1.2		225.9		228.3		-1.1
End of Period	223.1		226.1		-1.3		223.1		226.1		-1.3
INCOME STATEMENT ($millions)
Net Interest Income (FTE)	$289.3		$266.6		8.5	%	$867.8		$810.9		7.0	%
Provision for Loan and Lease Losses	6.9		7.9		-12.7		25.1		53.2		-52.8
Data Processing Services	239.0		166.3		43.7		622.4		481.4		29.3
Item Processing	10.3		11.2		-8.0		32.6		31.0		5.2
Trust Services	37.5		32.0		17.2		111.7		93.3		19.7
Service Charge on Deposits	25.0		25.4		-1.6		75.6		76.8		-1.6
Mortgage Banking	8.9		24.2		-63.2		27.5		63.5		-56.7
Net Investment Securities Gains (Losses)	0.5		16.7		n.m.		-		15.7		n.m.
All Other	46.7		49.2		-5.1		141.5		148.5		-4.7
Total Non-Interest Revenues	367.9		325.0		13.2		1,011.3		910.2		11.1
Salaries and Employee Benefits	231.5		199.4		16.1		647.3		587.4		10.2
Occupancy and Equipment	50.8		40.3		26.1		142.6		133.0		7.2
Intangible Amortization	8.3		3.4		144.1		19.2		17.8		7.9
Other	117.5		166.9		-29.6		336.0		340.5		-1.3
Total Non-Interest Expenses	408.1		410.0		-0.5		1,145.1		1,078.7		6.2
Tax Equivalent Adjustment	8.2		7.9		3.8		24.0		23.8		0.8
Pre-Tax Earnings	234.0		165.8		41.1		684.9		565.4		21.1
Income Taxes	78.6		25.5		208.2		231.6		160.9		43.9
Income as Adjusted (a)	155.4		140.3		10.8		$453.3		$404.5		12.1
Adjustments (a)	0.0		0.0		n.m.		0.0		(1.5)		n.m.
Net  Income	$155.4		$140.3		10.8	%	$453.3		$403.0		12.5	%
KEY  RATIOS
Net Interest Margin(FTE) / Avg. Earning Assets	3.42	%	3.53	%			3.57	%	3.65	%
Interest Spread (FTE)	3.11		3.21				3.27		3.33
Efficiency  Ratio	62.2		69.4				61.0		62.7
Efficiency  Ratio  without  Metavante	49.0		60.6				49.0		52.5
Return on Assets	1.63		1.66				1.67		1.63
Return on Equity	17.58		16.92				17.64		16.85
Return on Assets - Income as Adjusted (a)	1.63		1.66				1.67		1.63
Return on Equity - Income as Adjusted (a)	17.58		16.92				17.64		16.91
Equity / Assets (End of Period)	9.21		9.89				9.21		9.89
Notes:    (a) See reconciliation of Income as Adjusted to Net Income.
M&I  Corporation
Financial Information
(unaudited)
	As of
	September 30,		September 30,		Percent
ASSETS ($millions)	2004		2003		Change
Cash & Due  From  Banks	$887		$866		2.4	%
Trading Securities	36		40		-10.0
Short - Term  Investments	162		213		-23.9
Investment  Securities	6,079		5,497		10.6
Loans and Leases:
Commercial  Loans & Leases	8,326		7,279		14.4
Commercial  Real  Estate	9,127		8,074		13.0
Residential  Real  Estate	3,995		2,921		36.8
Home Equity Loans & Lines	5,033		4,187		20.2
Personal  Loans and Leases	1,664		2,174		-23.5
Total  Loans and Leases	28,145		24,635		14.2
Reserve for Loan & Leases Losses	(358)		(348)		2.9
Premises and Equipment, net	461		435		6.0
Goodwill and Intangibles	2,042		1,082		88.7
Other  Assets	1,526		1,329		14.8
Total  Assets	$38,980		$33,749		15.5	%
LIABILITIES & SHAREHOLDERS' EQUITY ($millions)
Deposits:
Noninterest Bearing	$4,753		$4,682		1.5	%
Bank Issued Interest Bearing Activity	9,835		9,912		-0.8
Bank Issued Time	3,529		3,307		6.7
Total Bank Issued Deposits	18,117		17,901		1.2
Wholesale Deposits	6,769		4,408		53.6
Total  Deposits	24,886		22,309		11.6
Short - Term  Borrowings	4,622		4,366		5.9
Long - Term  Borrowings	4,486		2,694		66.5
Other  Liabilities	1,398		1,043		34.0
Shareholders'  Equity	3,588		3,337		7.5
Total  Liabilities  &  Shareholders'  Equity	$38,980		$33,749		15.5	%
	Three Months Ended						Nine Months Ended
	September 30,		September 30,		Percent		September 30,		September 30,		Percent
	2004		2003		Change		2004		2003		Change
AVERAGE  ASSETS ($millions)
Cash & Due  From  Banks	$853		$742		15.0	%	$809		$751		7.7	%
Trading Securities	23		27		-14.8		23		23		0.0
Short - Term  Investments	166		260		-36.2		181		267		-32.2
Investment  Securities	5,935		5,157		15.1		5,819		5,152		12.9
Loans and Leases:
Commercial  Loans & Leases	8,191		7,304		12.1		7,864		7,320		7.4
Commercial  Real  Estate	8,926		8,000		11.6		8,611		7,817		10.2
Residential  Real  Estate	3,794		2,961		28.1		3,509		2,885		21.6
Home Equity Loans and Lines	4,894		4,100		19.4		4,674		4,074		14.7
Personal  Loans and Leases	1,695		2,231		-24.0		1,824		2,205		-17.3
Total  Loans and Leases	27,500		24,596		11.8		26,482		24,301		9.0
Reserve  for  Loan  &  Leases  Losses	(362)		(352)		2.8		(359)		(347)		3.5
Premises and Equipment, net	458		438		4.6		444		441		0.7
Goodwill and Intangibles	1,821		1,083		68.1		1,367		1,087		25.8
Other  Assets	1,622		1,489		8.9		1,584		1,452		9.1
Total  Assets	$38,016		$33,440		13.7	%	$36,350		$33,127		9.7	%
Memo:
Average Earning Assets	$33,624		$30,040				$32,505		$29,743
Average Earning Assets Excluding Investment Securities
Unrealized Gains/Losses	$33,616		$29,991				$32,467		$29,672
AVG  LIABILITIES & SHAREHOLDERS' EQUITY ($millions)
Deposits:
Noninterest Bearing	$4,638		$4,349		6.6	%	$4,490		$4,096		9.6	%
Bank Issued Interest Bearing Activity	9,913		10,072		-1.6		9,967		10,081		-1.1
Bank Issued Time	3,458		3,324		4.0		3,314		3,436		-3.6
Total Bank Issued Deposits	18,009		17,745		1.5		17,771		17,613		0.9
Wholesale Deposits	6,625		4,410		50.2		5,786		4,205		37.6
Total  Deposits	24,634		22,155		11.2		23,557		21,818		8.0
Short - Term  Borrowings	2,494		3,102		-19.6		3,058		3,304		-7.4
Long - Term  Borrowings	5,900		3,776		56.3		4,952		3,725		32.9
Other  Liabilities	1,470		1,117		31.6		1,350		1,083		24.7
Shareholders'  Equity	3,518		3,290		6.9		3,433		3,197		7.4
Total  Liabilities  &  Shareholders'  Equity	$38,016		$33,440		13.7	%	$36,350		$33,127		9.7	%
Memo:
Average Interest Bearing Liabilities	$28,390		$24,684				$27,077		$24,751
M&I  Corporation
Financial Information
(unaudited)
	Three Months Ended						Nine Months Ended
	September 30,		September 30,		Percent		September 30,		September 30,		Percent
	2004		2003		Change		2004		2003		Change
CREDIT  QUALITY (a)
Net Charge-Offs ($millions)	$6.7		$7.9		-15.2	%	$16.6		$43.5		-61.8	%
Net Charge-Offs / Average Loans & Leases	0.10	%	0.13	%			0.08	%	0.24	%
Loan and Lease Loss  Reserve ($millions)	$358.1		$348.1		2.9	%	$358.1		$348.1		2.9	%
Loan and Lease Loss  Reserve / Period-End  Loans & Leases	1.27	%	1.41	%			1.27	%	1.41	%
Non-Performing Loans & Leases (NPL)($millions)	$142.5		$187.3		-23.9	%	$142.5		$187.3		-23.9	%
NPL's / Period-End Loans & Leases	0.51	%	0.76	%			0.51	%	0.76	%
Loan and Lease Loss Reserve / Non-Performing Loans & Leases	251	%	186	%			251	%	186	%
MARGIN  ANALYSIS (b)
Loans and Leases:
Commercial  Loans & Leases	4.82	%	4.55	%			4.70	%	4.64	%
Commercial  Real  Estate	5.38		5.50				5.36		5.73
Residential  Real  Estate	5.48		5.72				5.49		6.05
Home Equity Loans and Lines	5.15		5.49				5.24		5.75
Personal  Loans and Leases	5.09		5.23				5.07		5.50
Total  Loans and Leases	5.17		5.22				5.14		5.42
Investment  Securities	4.99		4.27				4.95		4.89
Short - Term  Investments	1.55		0.81				1.20		0.99
Interest Income(FTE) / Avg. Interest Earning Assets	5.12	%	5.02	%			5.08	%	5.29	%
Interest Bearing Deposits:
Bank Issued Interest Bearing Activity	0.79	%	0.64	%			0.68	%	0.79	%
Bank Issued Time	2.47		2.42				2.41		2.55
Total Bank Issued Deposits	1.23		1.08				1.12		1.24
Wholesale Deposits	1.96		1.42				1.77		1.61
Total Interest Bearing Deposits	1.47		1.16				1.31		1.32
Short - Term  Borrowings	2.29		2.51				1.94		2.54
Long - Term  Borrowings	3.69		4.27				3.66		4.49
Interest Expense / Avg. Interest Bearing Liabilities	2.01	%	1.81	%			1.81	%	1.96	%
Net Interest Margin(FTE) / Avg. Earning Assets	3.42	%	3.53	%			3.57	%	3.65	%
Interest Spread (FTE)	3.11	%	3.21	%			3.27	%	3.33	%
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	$155.4		$140.3				$453.3		$404.5
Acquisition and Transition Related
Charges - Metavante	0.0		0.0				0.0		(1.5)
Net Income	$155.4		$140.3				$453.3		$403.0