** HK shares of China Petroleum & Chemical Corp 0386.HK, or Sinopec, fall 3.8% to HK$4.5, lowest since January 6

** Stock set for biggest one-day pct drop since March 9; second biggest pct loser on Hang Seng Composite Index on energy .HSCIE, which is down 1%

** Shanghai-listed stock 600028.SS slips 2.5% to 5.93 yuan, lowest since January 21

** Sinopec reports 36.8% y/y slump in 2025 net profit based on Chinese accounting standards, hurt by rising substitution by new energy sources, weak petrochemical margins

** Citi ("buy") sees co's refining margin coming under pressure into Q2 due to crude premium/freight cost spike, potentially slower domestic price hike, export controls

** YTD, HK stock down 3%, Shanghai-listed shares fall 3.2%

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))