** Shares of British oil and gas producer Harbour Energy HBR.L up 5.8% at 275.8 pence
** Stock among top gainers on London's mid caps index .FTMC, which is down 0.3%
** Co expects 2026 production of 475,000-500,000 barrels of oil equivalent per day (boepd), compared with previous estimate of 435,000-455,000 boepd
** HBR reports 2025 production of 474,000 boepd, compared with 258,000 boepd a year earlier
** Up to Wednesday's close, stock had risen 32.6% this year, compared with a 1.4% gain in FTMC
(Reporting by Simone Lobo in Bengaluru)
((Simone.Lobo@thomsonreuters.com, +919920570373))