Sources: Naperville-based Nicor for sale

Nicor Inc., the Chicago-area natural- gas utility with a market value of about $2 billion, is seeking a buyer, according to people with knowledge of the matter.

JPMorgan Chase & Co. is running the auction and started contacting potential buyers two to three months ago, said the people, who spoke on the condition of anonymity because the talks are private. Some utility companies and infrastructure funds were approached and decided the price for Nicor was too high to submit a bid, some of the people said.

Nicor shares rose as much as 8.2 percent before trading was halted at 2:34 p.m. by U.S. circuit breakers put in place in June. The curbs were put in place after the 20-minute rout on May 6 briefly erased $862 billion from the value of U.S. shares before prices rebounded.

Nicor rose $3.42, or 7.9 percent, to $46.94 at 2:50 p.m. in New York Stock Exchange composite trading.

Nicor Chief Executive Officer Russ Strobel, 58, is pursuing a sale as the Naperville-based company's shares trade at 15 times estimated 2011 earnings. That multiple compares with about 12 times for the Standard & Poor's 500 Utilities Index.

Annette Martinez, a spokeswoman for Nicor, said she couldn't comment.

Nicor is the parent of Nicor Gas, which serves more than two million customers in northern Illinois and the Chicago suburbs, according to Nicor's website. One of its predecessor companies provided gas for the lamps to light one of the debates between future U.S. President Abraham Lincoln and Stephen Douglas in 1858, according to the site.

In addition to the gas utility, Nicor owns Tropical Shipping, a freight business operating in the Bahamas and Caribbean.

Nicor shares closed at $43.52 yesterday in New York Stock Exchange composite trading, valuing the company at about $2 billion. The company had about $729 million of net debt as of Sept. 30.