Middle East Instability, AstraZeneca Setback Pull Down London's FTSE 100

London's leading FTSE 100 index experienced a downturn on Thursday, as renewed geopolitical tensions in the Middle East unsettled investors. This decline was further compounded by a sharp fall in AstraZeneca's shares, triggered by unfavourable outcomes from its latest clinical trials.

By 10:45 GMT, the FTSE 100, which comprises the UK's largest blue-chip companies, had dropped by 0.6%, settling at 10,417.63 points. In contrast, the mid-cap FTSE 250 index saw a modest increase of 0.1%, buoyed by positive performances from several domestically focused stocks. Investor confidence remained fragile, primarily due to recent US military actions against Iran, which reignited concerns about regional stability. However, fears of a broader conflict were somewhat alleviated after US President Donald Trump indicated he did not anticipate the situation escalating into a full-blown war.

Despite an increase in global oil prices, the energy sector's stocks collectively fell by 1%. Pharmaceutical companies recorded the most significant losses, with their shares plummeting by 6.2%, largely driven by AstraZeneca's poor showing. The drugmaker's shares alone plunged by 9.2% after Wainua, its experimental nerve disease treatment developed in collaboration with US-based Ionis Pharmaceuticals, failed to achieve its primary objective in a crucial late-stage trial. The trial aimed to reduce cardiovascular deaths and recurring heart complications.

Conversely, precious metal mining companies saw their shares rise by 2.6%. This gain was attributed to a weaker US dollar, which boosted gold prices and, consequently, increased demand for bullion. Market participants also continued to closely monitor developments in the Middle East for potential indicators regarding future inflation trends and interest rate adjustments.

Within the FTSE 250 index, Playtech, a gaming technology company, experienced a significant surge of 17.7%. Its shares climbed after the company projected its adjusted core earnings for 2026 would surpass market expectations, fueled by robust expansion in the United States and Latin America. Similarly, Computacenter, an IT services provider, recorded an increase of over 7%. The company announced its anticipation of annual earnings exceeding market forecasts, crediting strong demand for artificial intelligence infrastructure from its large-scale clients across North America and the United Kingdom.