Stock markets wobbled Wednesday as a "Santa Claus rally" showed signs of fatigue, with investors gauging the impact of the Omicron coronavirus variant on the economic recovery.

London's FTSE 100 outshone other markets, rising 0.7 percent to hit a nearly two-year high as UK traders returned from a long holiday.

But the traditional post-Christmas bullish mood waned in Asia and the eurozone, with markets there finishing lower.

The picture was also mixed on Wall Street, where the Nasdaq retreated even as both the Dow and S&P 500 edged to fresh records.

"The markets continue to reassess the economic impact of the Omicron variant," analysts at Schwab said in a note.

The United States has hit its highest-ever average of new Covid cases as Omicron spreads at a blistering pace, and the World Health Organization warned that a "tsunami" of infections would push health systems to the brink of collapse.

But investors have also clung to data showing a reduced risk of hospitalization, as well as the reality that trading volumes are extremely low in the period between Christmas and New Year's.

"With market activity much reduced for the holiday season, investors continue to tentatively price in a global recovery hitting a minor bump, and not a pothole," said Jeffrey Halley, senior market analyst at OANDA trading group.

"It's a positive drift in a thinly traded market," said Briefing.com analyst Patrick O'Hare. "There's really no news driving the market today."

Among individual stocks, Victoria's Secret shot up 12.2 percent after announcing that it will repurchase $250 million in company stock and confirmed an earlier sales forecast.

Biogen surged 9.5 percent following a report in the Korea Economic Daily that the drugmaker is in talks to be acquired by Samsung Group in a deal valued $42 billion.

New York - Dow: UP 0.2 percent at 36,488.63 (close)

Warnings from the WHO that the risk from the variant remains "very high" have compounded the sense of gloom that the pandemic is far from over
Warnings from the WHO that the risk from the variant remains "very high" have compounded the sense of gloom that the pandemic is far from over AFP / STR

New York - S&P 500: UP 0.1 percent at 4,793.06 (close)

New York - Nasdaq: DOWN 0.1 percent at 15,766.22 (close)

London - FTSE 100: UP 0.7 percent at 7,420.69 (close)

Frankfurt - DAX: DOWN 0.7 percent at 15,852.25 (close)

Paris - CAC 40: DOWN 0.3 percent at 7,161.52 (close)

EURO STOXX 50: DOWN 0.6 percent at 4,284.83 (close)

Tokyo - Nikkei 225: DOWN 0.6 percent at 28,906.88 (close)

Hong Kong - Hang Seng Index: DOWN 0.8 percent at 23,086.54 (close)

Shanghai - Composite: DOWN 0.9 percent at 3,597.00 (close)

Euro/dollar: UP at $1.1351 from $1.1310

Pound/dollar: UP at $1.3489 from $1.3434

Euro/pound: DOWN at 84.10 pence from 84.19 pence

Brent North Sea crude: UP 0.4 percent at $79.23 per barrel

West Texas Intermediate: UP 0.8 percent at $76.56 per barrel