NorthWestern Corporation Celebrates Transfer to the NYSE from Nasdaq

NEW YORK--(Business Wire)--
NorthWestern Corporation (d/b/a NorthWestern Energy), a Sioux
Falls, S.D.-based provider of electricity and natural gas in the Upper
Midwest and Northwest, today celebrated the transfer of the listing of
its stock to the NYSE from Nasdaq. The company's stock began trading
on the New York Stock Exchange on May 1 under the ticker symbol "NWE."

"We are pleased to welcome NorthWestern back to our family of
listed companies," said Catherine R. Kinney, Group EVP and Head of
Global Listings, NYSE Euronext. "We look forward to an outstanding
partnership with the company and providing NorthWestern with the
superior brand visibility, support and information services offered by
listing on NYSE Euronext markets."

"Today marks an exciting new chapter in NorthWestern's long
history with the NYSE," said Mike Hanson, President and Chief
Executive Officer. "Our return to the NYSE is a testament to
NorthWestern's steady stream of strong financial results over the last
three years. NorthWestern is well-positioned for growth, and we look
forward to continuing our relationship with the NYSE in order to
enhance shareholder value."

NorthWestern Corporation Chairman E. Linn Draper, Jr. and
President and Chief Executive Officer Michael J. Hanson commemorated
the transfer to the NYSE by ringing today's Opening Bell.

About NorthWestern Corporation (d/b/a NorthWestern Energy)

NorthWestern Energy is one of the largest providers of electricity
and natural gas in the Upper Midwest and Northwest, serving
approximately 650,000 customers in Montana, South Dakota and Nebraska.
More information on NorthWestern Energy is available on the Company's
Web site at www.northwesternenergy.com.

About NYSE Euronext

NYSE Euronext (NYX) operates the world's leading and most liquid
exchange group, and seeks to provide the highest levels of quality,
customer choice and innovation. Its family of exchanges, located in
six countries, includes the New York Stock Exchange, the world's
largest cash equities market; Euronext, the Eurozone's largest cash
equities market; Liffe, Europe's leading derivatives exchange by value
of trading; and NYSE Arca Options, one of the fastest growing U.S.
options trading platforms. NYSE Euronext offers a diverse array of
financial products and services for issuers, investors and financial
institutions in cash equities, options and derivatives, ETFs, bonds,
market data, and commercial technology solutions. NYSE Euronext's
nearly 4,000 listed companies represent a combined $ 30.9/ EUR 19.8
trillion in total global market capitalization (as of April 30, 2008),
more than four times that of any other exchange group. NYSE Euronext's
equity exchanges transact an average daily trading value of
approximately $161.9 / EUR 106.9 billion (as of April 30, 2008), which
represents more than one-third of the world's cash equities trading.
NYSE Euronext is part of the S&P 500 index and the only exchange
operator in the S&P 100 index. For more information, please visit
www.nyx.com.

Cautionary Note Regarding Forward-Looking Statements

This press release may contain forward-looking statements,
including forward-looking statements within the meaning of the Private
Securities Litigation Reform Act of 1995. Such forward-looking
statements include, but are not limited to, statements concerning NYSE
Euronext's plans, objectives, expectations and intentions and other
statements that are not historical or current facts. Forward-looking
statements are based on NYSE Euronext's current expectations and
involve risks and uncertainties that could cause actual results to
differ materially from those expressed or implied in such
forward-looking statements. Factors that could cause NYSE Euronext's
results to differ materially from current expectations include, but
are not limited to: NYSE Euronext's ability to implement its strategic
initiatives, economic, political and market conditions and
fluctuations, government and industry regulation, interest rate risk
and U.S. and global competition, and other factors detailed in NYSE
Euronext's reference document for 2007 ("document de reference") filed
with the French Autorite des Marches Financiers (Registered on May 15,
2008 under No. R. 08-054), 2007 Annual Report on Form 10-K and other
periodic reports filed with the U.S. Securities and Exchange
Commission or the French Autorite des Marches Financiers. In addition,
these statements are based on a number of assumptions that are subject
to change. Accordingly, actual results may be materially higher or
lower than those projected. The inclusion of such projections herein
should not be regarded as a representation by NYSE Euronext that the
projections will prove to be correct. This press release speaks only
as of this date. NYSE Euronext disclaims any duty to update the
information herein.

NYSE Euronext
Annmarie Gioia, 212-656-5437
agioia@nyse.com

Copyright Business Wire 2008