** Utility firm TXNM Energy's TXNM.N shares rise 9.2% to $57.75 premarket
** Company says it would be acquired by Blackstone's BX.N infrastructure unit in an $11.5 bln deal, including debt
** TXNM shareholders will receive $61.26/share, a premium of around 15% to stock's last closing price - based on Reuters calculation and LSEG data
** The deal is expected to be completed in the second half of 2026
** As of last close, shares up 7.5% YTD
(Reporting by Sumit Saha in Bengaluru)
((Sumit.Saha@thomsonreuters.com;))