NiSource Issues $500 Million in Two Series of Notes

MERRILLVILLE, Ind., Nov. 23, 2011 /PRNewswire/ — NiSource Inc. (NYSE: NI) today
announced that its finance subsidiary, NiSource Finance Corp., has completed the
sale of $250 million aggregate principal amount of 4.45% Notes due 2021 (the
“Notes due 2021″) and $250 million aggregate principal amount of 5.80% Notes due
2042 (the “Notes due 2042″) in an underwritten public offering. NiSource Inc.
will fully and unconditionally guarantee NiSource Finance’s obligations under
the notes.

NiSource Finance intends to use the net proceeds from the sale of the Notes due
2021 to contribute to the pension plans of NiSource Inc. and certain of its
subsidiaries and the net proceeds from the sale of the Notes due 2042 to
purchase notes in NiSource Finance’s previously announced tender offer that
commenced on November 14, 2011.

Barclays Capital Inc., Citigroup Global Markets Inc. and J.P. Morgan Securities
LLC acted as joint book-running managers for the offering. BNP Paribas
Securities Corp., Deutsche Bank Securities Inc. and Scotia Capital (USA) Inc.
acted as senior co-managers. KeyBanc Capital Markets Inc., Loop Capital Markets
LLC and Mizuho Securities USA Inc. acted as co-managers.

About NiSource
NiSource Inc. (NYSE: NI), based in Merrillville, Ind., is a Fortune 500 company
engaged in natural gas transmission, storage and distribution, as well as
electric generation, transmission and distribution. NiSource operating companies
deliver energy to 3.7 million customers located within the high-demand energy
corridor stretching from the Gulf Coast through the Midwest to New England.
Together, NiSource’s gas transmission and storage companies operate a
15,000-mile network of natural gas pipelines, 37 storage fields and serve some
of the nation’s largest and fastest-growing energy markets in the Northeast,
Midwest and Mid-Atlantic regions. Information about NiSource and its
subsidiaries is available via the Internet at www.nisource.com. NI-F

Forward-Looking Statements
This news release includes forward-looking statements within the meaning of
Section 27A of the Securities Act of 1933, as amended, and Section 21E of the
Securities Exchange Act of 1934, as amended. Those statements include statements
regarding the intent, belief or current expectations of NiSource and its
management. Although NiSource believes that its expectations are based on
reasonable assumptions, it can give no assurance that its goals will be
achieved. Readers are cautioned that the forward-looking statements in this news
release are not guarantees of future performance and involve a number of risks
and uncertainties, and that actual results could differ materially from those
indicated by such forward-looking statements. Important factors that could cause
actual results to differ materially from those indicated by such forward-looking
statements include, but are not limited to, the following: weather; fluctuations
in supply and demand for energy commodities; growth opportunities for NiSource’s
businesses; increased competition in deregulated energy markets; the success of
regulatory and commercial initiatives; dealings with third parties over whom
NiSource has no control; actual operating experience of NiSource’s assets; the
regulatory process; regulatory and legislative changes; the impact of potential
new environmental laws or regulations; the results of material litigation;
changes in pension funding requirements; changes in general economic, capital
and commodity market conditions; and counterparty credit risk, and the matters
set forth in the “Risk Factors” section in NiSource’s 2010 Form 10-K and Forms
10-Q, many of which risks are beyond the control of NiSource. NiSource expressly
disclaims a duty to update any of the forward-looking statements contained in
this release.