Both the STOXX 50 and the STOXX 600 reversed early gains to fall 0.1% and 0.3%, respectively, on Thursday afternoon, retreating from fresh record highs reached earlier in the session. Initial optimism surrounding the reopening of the US government faded, while a series of disappointing corporate updates also weighed on sentiment. Siemens shares tumbled more than 5% after the company issued a disappointing profit outlook for next year. Novo Nordisk slipped 0.8% following reports that it plans to issue a bond to finance its acquisition of Akero Therapeutics. 3i Group plunged over 18% after warning of a more cautious outlook, and Deutsche Telekom reversed early gains to trade 1% lower, even after raising its 2025 guidance once again. On the other hand, Merck surged 5.3% after reporting operating earnings that exceeded market expectations. Burberry pared earlier gains but still added 0.8%, as the company recorded its first sales increase in two years.