Global stocks were mixed Thursday in slow end-of-year trading as markets weighed the efforts to limit the health and economic effects of the latest fast-spreading Covid-19 wave.

The Omicron variant has led to record new caseloads of Covid-19 worldwide, but markets have remained sanguine in light of research suggesting the health effects will be milder than with earlier variants.

Paris and Frankfurt both climbed but London fell, and Wall Street paused its rally, with both the Dow and S&P 500 retreating from all-time highs.

"Worries about the Omicron variant have receded, but the speed of its spread is tempering sentiment," analysts at Charles Schwab wrote.

The world's top economy hit its highest-ever seven-day average of new Covid-19 cases Wednesday, and though the health impact is less severe the volume of infections is having an impact on the travel and service industries.

The US Centers for Disease Control and Prevention on Thursday urged Americans to avoid cruise travel, even if they are vaccinated, citing the surge in cases on ships spurred by the Omicron variant.

"The virus that causes Covid-19 spreads easily between people in close quarters on board ships, and the chance of getting Covid-19 on cruise ships is very high, even if you are fully vaccinated and have received a Covid-19 vaccine booster dose," the CDC said.

Markets are "showing some resiliency in the face of expectations that the Fed could accelerate its monetary tightening campaign and as inflation pressures persist," Schwab said.

One bright spot for traders was a lower-than-expected US jobless claims report for last week.

Asia's main indices ended mixed, while Chinese artificial intelligence start-up SenseTime a big winner with its shares jumping 23 percent on its Hong Kong debut.

Aviation giant Emirates said it expects business to grow next year despite the surge in global coronavirus cases.

Tokyo closed lower in its last trading day of 2021, but the benchmark Nikkei index rose nearly five percent for the year to its highest annual close since the 1989 boom.

Friday marks the final session of the year in other leading markets, including New York. Major US indices have won double-digit gains thus far in 2021, with the S&P 500 currently up more than 27 percent.

New York - Dow: DOWN 0.2 percent at 36,398.08 (close)

Fears over the Omicron coronavirus variant have weighed on markets
Fears over the Omicron coronavirus variant have weighed on markets AFP / Sajjad HUSSAIN

New York - S&P 500: DOWN 0.3 percent at 4,778.73 (close)

New York - Nasdaq: DOWN 0.2 percent at 15,741.56 (close)

London - FTSE 100: DOWN 0.2 percent at 7,403.01 (close)

Frankfurt - DAX: UP 0.2 percent at 15,884.86 (close)

Paris - CAC 40: UP 0.2 percent at 7,173.23 (close)

EURO STOXX 50: UP 0.5 percent at 4,306.07 (close)

Tokyo - Nikkei 225: DOWN 0.4 percent at 28,791.71 (close)

Hong Kong - Hang Seng Index: UP 0.1 percent at 23,112.01 (close)

Shanghai - Composite: UP 0.6 percent at 3,619.19 (close)

Euro/dollar: DOWN at $1.1329 from $1.1349

Pound/dollar: UP at $1.3498 from $1.3490

Euro/pound: DOWN at 83.92 pence from 84.13 pence

Dollar/yen: UP at 115.07 yen from 114.95 yen

Brent North Sea crude: UP 0.1 percent at $79.32 per barrel

West Texas Intermediate: UP 0.6 percent at $76.99 per barrel