NorthWestern Energy gains on $3.6 billion buyout offer from Black Hills

** Shares of utility NorthWestern Energy Group NWE.O gain 4.5% to $57.39

** Co says it has agreed on a deal to be acquired by Black Hills BKH.N for $3.6 billion

** NWE shareholders will receive 0.98 shares of BKH for each held or $59.14 per share, representing a premium of 7.66% to NorthWestern's last close, according to Reuters calculation

** Barclays Analyst sees the acquisition as 1% and 4% accretive in 2027 and 2028, respectively

** "The accretion of 100 basis points to growth should help valuation of both very cheap stocks and the larger balance sheet helps to fund the extra growth opportunities both companies have" said Siebert Williams Shank analyst Chris Ellinghaus

** The all-stock deal will create a regional regulated natural gas utility company with a pro forma market capitalization of roughly $7.8 billion and a combined enterprise value of $15.4 billion

** Deal expected to close within 12 to 15 months

** Including session's moves, NWE shares up 7.4% YTD