** Power producer Constellation Energy CEG.O shares down 3% before the bell on Mon to $279.18 after secondary offering news

** Baltimore, Maryland-based CEG kicks off 11 mln share offering by certain existing holders

** In addition, CEG intends to repurchase 2 mln of offering shares from underwriters Morgan Stanley and JP Morgan

** CEG has ~361.19 mln shares outstanding. Private equity firm Energy Capital Partners is the top shareholder with ~22 mln shares, per LSEG data

** Last month, the largest U.S. nuclear power operator beat Wall Street's Q1 profit estimates on rising demand and contributions from recently acquired Calpine assets

** Through Fri close, CEG stock down roughly 19% YTD and well underperforming nearly 4% gain in S&P 500 Utilities .SPLRCU

** 20 of 23 analysts rate the stock "strong buy" or "buy", 3 "hold"; median PT $362.23, according to LSEG data