Bank of Communications shares surged 12.58 per cent yesterday to close at a record high of HK$11.28. The stock's biggest advance since December last year followed speculation its biggest shareholder, HSBC, may raise its stake through the H-share market. An HSBC spokeswoman declined to comment, reiterating the lender was in talks with mainland regulators over a proposal to raise its stake. Bocom has been lagging rivals ICBC and China Construction Bank, whose share prices have risen 24.3 per cent and 44 per cent this year. 'They probably won't make such an emotive announcement before the 17th Party Congress.' said Lewis Wan at Pride Investment Group. HSBC's stake was diluted to 18.6 per cent from 19.9 per cent when Bocom listed its A shares in May. Goldman Sachs said HSBC could top up its stake to 19.9 per cent by next year.