MERRILLVILLE, Ind. (AP) ¿ Energy holding company NiSource Inc. said Monday it offered $600 million in senior notes due in 2016 to help refinance debts due this year and in 2010.

NiSource said it will use the proceeds from the offering to finish refinancing its debt scheduled to mature in November, and to refinance a portion of its debts scheduled to mature in November 2010. The notes are being sold by the NiSource Finance Corp. unit.

The book-running managers for the offering are Citigroup Global Markets Inc., JPMorgan Securities Inc., and Wachovia Capital Markets LLC.

NiSource also said Standard & Poor's Ratings Service raised its outlook to "Stable" from "Negative" because of the planned offering and other efforts to shore up the company's financial position. The service has a BBB- corporate credit rating, which is investment grade, but only one degree above "junk" status.

NiSource shares closed at $8.33 Monday.

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