The IBEX 35 opened Monday with a slight decline, though it remained comfortably above 17,100 points and near historic highs, in a session marked by a transitional tone due to the shortened Christmas week and some profit-taking following this year's strong gains.

Risk appetite remains supported by investment flows into equities, precious metals, and commodities, as markets await delayed U.S. data that, according to median forecasts, would point to an annualized growth rate of 3.2% in the third quarter, in a report to be released on Tuesday.

Still, caution may prevail in the short term, with a certain sense of fatigue after the sharp rally so far this year, and many managers may choose to wait until 2026 to define the future course.

Analysts at Bankinter noted on their Telegram channel that the focus will be "on taking positions ahead of 2026 and the 'fear of missing out' (FOMO)."

"We believe that in 2026 the market will be supported by a global expansion cycle and inflation that is higher than desired but not problematic, interest rates that will continue to fall in the U.S., a lower geopolitical risk premium, and corporate profits that will grow at a low double-digit rate."

On the geopolitical front, talks held in Florida between representatives of the United States, Europe, and Ukraine to try to end the war between Kiev and Moscow were described as productive by U.S. envoy Steve Witkoff, although the Kremlin maintains that European and Ukrainian changes to Washington's proposals do not improve the prospects for peace.

On the macroeconomic front, the day lacks significant references. In addition to the third-quarter GDP update, Tuesday will bring U.S. data on durable goods orders, industrial production, and Conference Board consumer confidence.

The atypical trading calendar this week is also weighing on sentiment: Wednesday will see an early close at 1300 GMT on the Spanish stock exchange, and there will be no trading on Thursday and Friday due to Christmas.

With seven sessions remaining to close out the year, the IBEX 35 is up nearly 48% in 2025 and has risen more than 4.5% in December, paving the way for a sixth consecutive month of gains and the largest monthly increase since May.

On Monday, Spain's IBEX 35 blue-chip index fell 33.70 points, or 0.20%, to 17,136.10 points at 0805 GMT, while the pan-European FTSE Eurofirst 300 index slipped 0.09%.

In the banking sector, Santander lost 0.25%, BBVA slipped 0.08%, Caixabank fell 0.10%, Sabadell dropped 0.29%, Bankinter shed 0.60%, and Unicaja Banco rose 0.14%.

Among major non-financial stocks, Telefónica dropped 0.64%, Inditex was unchanged, Iberdrola lost 0.63%, Cellnex fell 0.59%, and oil company Repsol gained 0.54%.

(Reporting by Tomás Cobos; editing by Benjamín Mejías Valencia)