** Shares of Canadian energy company ARC Resources ARX.TO rise 21.5% to C$31.31, highest since June 2025
** Shell SHEL.L agrees to buy ARC Resources in a deal valued at $16.4 billion, including debt, expected to boost its output by 370,000 barrels of oil equivalent per day
** Under the deal, Shell will pay ARC's shareholders C$8.20 in cash and 0.40247 Shell shares for each ARC share
** Deal is expected to close in the second half of this year
** Including session's move, stock up 21.83% YTD
(Reporting by Pooja Menon in Bengaluru)
((Pooja.Menon@thomsonreuters.com;))