European equities finished lower in thin trade on Monday — the first day of the final week of 2015 — as oil prices fell.
London's FTSE index was closed for a U.K. public holiday, as were Irish, Canadian and Australian stock markets.
The pan-European STOXX 600 index ended down around 0.5 percent. France's CAC 40 closed roughly 1.0 percent lower, while Germany's DAX fell 0.7 percent.
U.S. stocks also under-performed on Monday, as a renewed slide in oil prices weighed on equity markets.
U.S. crude futures for February were trading more than 3 percent lower on the day, at around $36.90 per barrel, when Europe's main stock markets closed.
Brent was down some 2.5 percent, at just under $37 per barrel.
This slip in oil prices caused European energy stocks to fall, with Repsol, Royal Dutch Shell and Subsea 7 posting sharp losses of more than 2.5 percent.
However, Seadrill was the worst hit, with shares sinking 5.3 percent.
ArcelorMittal slips 5%
Shares in ArcelorMittal fell to near the bottom of indexes, ending down more than 5 percent on profit taking. This followed a surge in its shares last week, after a report that China was likely to cut its steel surplus.
Shares of Banca Monte dei Paschi di Siena finished slightly higher after the bank reached a deal to sell a portfolio of non-performing loans worth 1 billion euros ($1.1 billion) to a Deutsche Bank vehicle, Reuters reported.
The news boosted shares in another Italian bank, Banca Pop Milano, which ended up 1.7 percent.
Shares of Adidas were off over 1 percent after the company's CFO told German newspaper Boersen-Zeitung that the sports retailer expected sourcing costs to rise next year because of negative currency effects.