Marshall & Ilsley Corporation Announces $350 Million Discretionary Equity Issuance...

Marshall & Ilsley Corporation Announces $350 Million Discretionary Equity
Issuance Plan

MILWAUKEE, May 19 /PRNewswire-FirstCall/ -- Marshall & Ilsley Corporation
(NYSE: MI) (M&I) announced today that it has commenced a discretionary equity
issuance plan pursuant to which it will offer shares of its common stock
having aggregate sales proceeds of up to $350 million. Sales of the shares of
common stock, if any, will be made by means of ordinary brokers' transactions
on the New York Stock Exchange or otherwise at then prevailing market prices.
Morgan Stanley & Co. Incorporated will act as M&I's sales agent for the
offering. M&I has filed a prospectus supplement to its existing automatic
shelf registration statement on file with the Securities and Exchange
Commission (SEC) in connection with the offering.

M&I intends to use the net proceeds of any sales under the program for general
corporate purposes and may contribute some portion of the net proceeds to the
capital of its subsidiaries, which will use these contributions for their
general corporate purposes.

To the extent that M&I's Board of Directors determines at a future date that
it is in the best interests of M&I and its shareholders to do so, M&I may
elect to repurchase a portion of its Senior Preferred Stock, Series B issued
to the United States Department of the Treasury as part of its Capital
Purchase Program with all or a portion of the remaining net proceeds of this
offering. Any such repurchase would be subject to consultation with and
approval by M&I's banking regulators. In the event that M&I chooses to seek
such approval, there can be no assurance that such approval would be granted.

This press release does not constitute an offer to sell or a solicitation of
an offer to buy any securities, nor shall there be any sale of these
securities in any state or jurisdiction in which such an offer, solicitation
or sale would be unlawful prior to registration or qualification under the
securities laws of any such state or jurisdiction.

The offering will be made pursuant to M&I's effective shelf registration
statement filed with the SEC. Investors should read the prospectus supplement
and the accompanying prospectus for more complete information about M&I and
the offering. These documents can be obtained free of charge by visiting IDEA
on the SEC's website at www.sec.gov. Alternatively, copies may be obtained
from Morgan Stanley & Co. Incorporated, 180 Varick Street, Second Floor, New
York, New York 10014, Attention: Prospectus Department, Toll Free (866)
718-1649, or by email atprospectus@morganstanley.com.

About Marshall & Ilsley Corporation

Marshall & Ilsley Corporation (NYSE: MI) is a diversified financial services
corporation headquartered in Milwaukee, Wis., with $61.8 billion in assets.
Founded in 1847, M&I Marshall & Ilsley Bank is the largest Wisconsin-based
bank, with 193 offices throughout the state. In addition, M&I has 53 locations
throughout Arizona; 32 offices in Indianapolis and nearby communities; 36
offices along Florida's west coast and in central Florida; 16 offices in
Kansas City and nearby communities; 26 offices in metropolitan Minneapolis/St.
Paul, and one in Duluth, Minn.; and one office in Las Vegas, Nev. M&I's
Southwest Bank subsidiary has 17 offices in the greater St. Louis area. 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.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of
the safe harbor provisions of the Private Securities Litigation Reform Act of
1995. Such forward-looking statements include, without limitation, statements
regarding certain plans, expectations and goals that are preceded by, followed
by, or that include words such as "may," "expects," "anticipates," "estimates"
or "believes." 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) M&I's exposure to the
deterioration in the commercial and residential real estate markets, along
with the deterioration in the U.S. economy as a whole, which could result in
increased charge-offs and increases in M&I's allowance for loan and lease
losses, (ii) various other factors, including changes in economic conditions
affecting borrowers, new information regarding outstanding loans and
identification of additional problem loans, which could require an increase in
M&I's allowance for loan and lease losses, (iii) M&I's ability to maintain
required levels of capital, (iv) the impact of recent and future legislative
initiatives on the financial markets or on M&I, (v) M&I's exposure to the
actions and potential failure of other financial institutions, (vi) volatility
in M&I's stock price, and (vii) those factors referenced in Item 1A. Risk
Factors in M&I's annual report on Form 10-K for the year ended December 31,
2008. Readers are cautioned not to place undue reliance on these
forward-looking statements, which reflect only M&I's belief as of the date of
this press release. Except as required by federal securities law, M&I
undertakes no obligation to update these forward-looking statements or reflect
events or circumstances after the date of this press release.

SOURCE Marshall & Ilsley Corporation

Greg Smith, senior vice president, chief financial officer, +1-414-765-7727,
or Dave Urban, vice president, director of investor relations,
+1-414-765-7853, both of Marshall & Ilsley Corporation