The FTSE 100 fell sharply at the open after credit ratings agency Moody’s downgraded the US sovereign credit outlook, resulting in a flight to safety.
An hour into trade, the blue chip index was 48 points down at 8,637, a loss of just over half a percent.
Investment trusts with a large exposure to the US are leading the fallers, including Scottish Mortgage Investment Trust PLC (LSE:SMT), Pershing Square Holdings (LSE:PSH), Polar Capital Technology Trust PLC (LSE:PCT) and Alliance Witan PLC (LSE:ALW).
Topping the risers is precious metals miner Fresnillo, up 3.8% as gold and silver prices climb.
Meanwhile, Diageo PLC (LSE:DGE) has reported an improved rate of revenue growth in the past quarter and launched a new efficiency programme, but said sales trends were boosted by "phasing" and are likely to reverse in the current quarter.
National Express owner Mobico Group PLC (LSE:MCG) has reported first-quarter results showing 9% revenue growth, with an increase from Spanish arm ALSA offsetting declines in the UK and Germany.
