The IBEX 35 opened Thursday with a slight uptick, trading in record territory, buoyed by mounting bets on a Federal Reserve rate cut next week and easing tensions in debt markets.

If the gains hold, the benchmark index--now trading just above its all-time closing high of 16,616 points set on November 12--would notch its ninth consecutive session of advances, marking its best streak since the ten-session run between August 4 and August 15.

Expectations for U.S. rate cuts were bolstered by weaker-than-expected data: private sector job creation saw its steepest drop in more than two and a half years, according to payroll processor ADP, while a survey from the Institute for Supply Management revealed contraction in services sector employment in November and a seven-month low in the prices paid sub-index.

Analysts at Renta 4 highlighted that the ISM report--despite the main index rising at its fastest pace in nine months--showed a decline in new orders and moderation in prices, while the ADP figures further reinforced the case for monetary easing.

"Taken together, these data continue to support a 25 basis point rate cut by the Fed on December 10 (98% probability), pending tomorrow's key inflation reading: the core personal consumption expenditures (PCE) deflator, with expectations of a slight moderation in September (2.8%e vs 2.9% prior)," the analysts said.

Attention now turns to the PCE deflator, the U.S. central bank's preferred inflation gauge, which is set to be released on Friday.

According to LSEG's IRPR money market futures tool, markets now assign an 85% probability to a 25 basis point rate cut when the Fed meets next week.

Stability also returned to fixed income markets. Following recent concerns over Japan's finances--amid stimulus plans largely funded by new debt--the latest Tokyo government bond auction drew the highest demand in more than six years.

These developments helped stabilize markets after a sell-off had pushed ultra-long yields to record highs and rattled global debt earlier in the week.

On the geopolitical front, "the path of peace talks in Ukraine remains uncertain," U.S. President Donald Trump said Wednesday, following "reasonably good" discussions between Russian President Vladimir Putin and U.S. envoys.

At 0815 GMT on Thursday, Spain's IBEX 35 was up 50.20 points, or 0.30%, at 16,635.90, while the pan-European FTSE Eurofirst 300 index advanced 0.27%.

In the banking sector, Santander gained 0.79%, BBVA rose 0.45%, Caixabank advanced 1.28%, Sabadell was up 0.78%, Bankinter slipped 0.83%, and Unicaja Banco added 0.61%.

Among major non-financials, Telefónica fell 0.47%, Inditex climbed 0.64%, Iberdrola was little changed, Cellnex gained 0.28%, and oil company Repsol edged up 0.06%.

On the downside, CIE Automotive dropped 7% after Mahindra & Mahindra placed its 3.58% stake in the Spanish auto parts company.

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