The US Federal Energy Regulatory Commission said it was giving a $7.9 billion merger between Constellation Energy Group and Exelon Corp. a green light. The deal between the two energy giants is expected to close Monday. The new company will be based in Chicago, The Baltimore Sun reported Saturday. FERC had been investigating the merger on antitrust concerns. In a 48-page ruling, FERC said the combined company \"will not harm competition in the relevant geographic markets.\" As a condition of the merger, the companies had agreed to give Baltimore Gas and Electric residential customers a $100 rate credit, which customers should receive within 90 days of the merger, the newspaper said. The companies also agreed to make other changes. In a separate agreement, however, it was announced Friday that Constellation had agreed to pay $245 million to settle the regulator\'s charges that it manipulated the wholesale energy market between September 2007 and December 2008. The company admitted to no wrongdoing, but settled the allegations, because, \"we believe it is in the interest of all parties to settle this case and avoid expensive, protracted litigation,\" said Constellation Chairman and Chief Executive Officer Mayo Shattuck III in a statement.