Sterling rises 0.5% versus weaker dollar; flat versus euro

LONDON (Reuters) - The pound rose around half a percent against a weaker dollar on Thursday, but was little changed against the euro, as Brexit-related risks and speculation about negative interest rates continue to limit the pound's gains.The safe-haven dollar fell to a near two-month low as global risk appetite was boosted by investors' optimism about economies re-opening. A 750-billion-euro stimulus plan in Europe lifted regional stock indices and the euro.The pound gained as much as 0.6%..