(Bloomberg) -- European stocks posted the biggest weekly decline in over three months, as Danish drugmaker Novo Nordisk A/S sank 21% after a study showed underwhelming results from its obesity drug trial.

The Stoxx Europe 600 Index fell 0.9% by the close, with Novo plunging to its lowest since August 2023, as its experimental obesity shot CagriSema helped patients lose an average of 20.4% of their weight over 68 weeks, short of the 25% weight loss that Novo had repeatedly predicted.

Novo is Europe’s biggest company by market capitalization and the second-heaviest weighted member in the Stoxx 600.

The OMX Copenhagen 25 Index slid 2.9%, also hurt by a decline in Zealand Pharma A/S after it said the US Food and Drug Administration failed to approve its new drug application for glepaglutide for treating short bowel syndrome.

The benchmark Stoxx 600 is now up about 5% in 2024, sharply underperforming US peers. A rally in the index faltered this month as the Federal Reserve indicated it could slow the pace of easing next year as its 2% inflation target remains out of reach. Trade concerns are also rising, with US President-elect Donald Trump threatening the European Union with tariffs if its member countries don’t buy more American oil and gas.

Investors are also mulling the possibility of an American government shutdown after the Republican-led House rejected a temporary funding plan backed by Trump.

“Going into the week, investor sentiment was too bullish, both in Europe and the US,” said Panmure Liberum strategist Joachim Klement. Central banks “have triggered a reassessment of the interest rate outlook. We do not expect any major moves until the new year.”

Traders also navigated the quarterly “triple-witching” event, which saw some $6.5 trillion worth of options tied to individual stocks, indexes and exchange-traded funds expire on Friday.

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