Hedge funds globally suffered their second-worst week in four years during the final full trading week of July as continuing concerns about the spread of US credit problems took their toll on performance. The Hedge Fund Research index of investable hedge funds, a widely followed performance benchmark, fell by just over 3 per cent in the week beginning July 23 as global markets fluctuated wildly, representing the worst week of performance since late March, when the index fell 3.4 per cent amid a sudden sharp market sell-off. HFR was due to report full-year figures for its entire database of hedge fund managers late Tuesday, as investors keenly await indications of July performance from index providers and hedge fund managers.