The $245 million settlement that Baltimore's Constellation Energy Group agreed to pay is the largest of its kind to resolve allegations of market manipulation with the Federal Energy Regulatory Commission.

Details of the settlement emerged Monday, the same day Chicago-based Exelon Corp. closed on its $7.9 billion takeover of Constellation. The sale creating the largest non-utility energy provider in the United States ushers Baltimore's last Fortune 500 company out of town. The New York Stock Exchange will de-list Constellation shares Tuesday.

Federal energy regulators approved both the sale and the settlement late Friday.

The settlement between Constellation and FERC resolves allegations that the company intended to manipulate New York wholesale energy markets by making trades to influence certain energy prices from September 2007 to December 2008. Those transactions, in turn, benefited other holdings in the company's energy-trade portfolio, FERC alleged.

While Constellation disagreed with FERC's findings and admitted no wrongdoing, the company said it was in its best interest to settle and move ahead with the merger.

Standard & Poor's described the settlement Monday as a "record-setting fine."

Under the settlement's terms, Constellation agreed to pay a $135 million civil penalty and "disgorge" — or give back — "unjust profits" of $110 million.

FERC said Constellation's $135 million fine is the largest since the Energy Policy Act of 2005 strengthened the federal regulator's authority to assess penalties of up to $1 million per day for violating laws governing the electric and gas industries. The previous record was a $30 million penalty imposed on a natural gas trader for market manipulation in April, according to FERC.

Constellation's $110 million disgorgement also is the largest since Energy Transfer Partners agreed to pay $20 million to settle allegations of gas market price manipulation in 2009.

Maryland could benefit from a slice of the $110 million, which will be disbursed in two ways.

Each of the six U.S. regional grid operators, including PJM, which covers Maryland, will receive $1 million to enhance its ability to detect market manipulation.

The remaining $104 million will be directed to a fund set up for the "benefit of electric energy consumers" in affected states. It will be split among three grid operators, with the New York market receiving $78 million, the New England market $20 million and PJM $6 million.

State agencies, such as public service commissions or state consumer advocates, can request money from the fund, which will be overseen by a FERC administrative judge, according to the settlement.

The Maryland Office of People's Counsel, which represents residential customers on utility matters, expects the state to receive some of that money for Maryland ratepayers.

People's Counsel Paula M. Carmody said that her office would be part of any proceeding dividing the money for the PJM market under what she described as a significant settlement.

"It could send real signals that they're serious about market manipulations," said Carmody, whose office raised concerns about market power in Constellation's merger. "Customers are at the mercy of what goes on in those markets with deregulation. It's important that FERC takes a tough stance to protect customers at the state level."

A spokeswoman for the Maryland Public Service Commission said Monday that it is studying FERC's settlement.

FERC launched the investigation, which wasn't made public until Friday, in January 2008 after receiving two anonymous hotline calls. The federal agency focused on trades from September 2007 to December 2008 by four employees of Constellation's East Power Trading Group.

The regulator's enforcement office determined that the alleged market manipulation "resulted in widespread economic losses to market participants who bought and sold energy" in the New York and New England wholesale markets, according to the FERC order approving the settlement.