** U.S. refiners are poised to clock annual gains in 2025 and are among the top performers on the S&P 500 energy index .SPNY

** The stocks were boosted after U.S. refining margins rebounded from multiyear lows in 2024, as supply shortages tied to geopolitical tensions in Ukraine supported stronger pricing

** The 3-2-1 crack spread CL321-1=R, which measures refining margins, rose over 18% through 2025 and is set to snap a two-year losing streak

** Top US refiners Valero Energy VLO.N surged over 34% in 2025, followed by Marathon Petroleum's MPC.N 17.4% gain and Phillips 66's PSX.N 13.7% rise

** During the year PSX focused on streamlining operations, after a long-drawn proxy battle with activist investor Elliott Investment Management

** It also acquired full ownership of two major U.S. refineries, collectively known as WRB Refining, in a $1.4 billion deal

** Smaller refiners HF Sinclair DINO.N gained just over 30%, Delek US Holdings DK.N rose 61.6%, while Par Pacific Holdings PARR.N more than doubled

** Meanwhile, S&P 500 energy index has risen over 4% YTD with VLO, EQT Corp EQT.N MPC and PSX leading the gains

(Reporting by Vallari Srivastava in Bengaluru)

((Srivastava.Vallari@thomsonreuters.com;))