European stock markets were close to flat Monday but Wall Street enjoyed solid gains, buoyed by coronavirus vaccine hopes and big-ticket deals.
Trials on one of the most advanced vaccines resumed at the weekend after pausing when a volunteer fell ill.
British regulators gave AstraZeneca and the University of Oxford the go-ahead to push on following an investigation, while the drug group said it remained hopeful the vaccine would still be available "by the end of this year, early next year".
Meanwhile pharma giant Gilead said it would buy breast cancer drug maker Immunomedics for $21 billion.
And in tech, Japan's SoftBank group announced the sale of British chip designer Arm to US-based NVIDIA for $40 billion, while the US Treasury said it had received a bid involving Oracle for video-sharing app TikTok's US operations.
"US stocks are rebounding noticeably from a two-week pullback from record high territory, with a flood of M&A activity and a host of news on the Covid-19 vaccine/treatment front fostering the recovery," Charles Schwab analysts wrote.
Europe was weighed down as countries reported rising coronavirus infections and some issued new measures to control the spread of Covid-19.
The World Health Organization's European chief Hans Kluge told AFP Monday that the autumn will be "tougher" with "more mortality" from Covid-19.
And Britain's parliament found itself arguing about Brexit again, with threats of rebellion and resignations over Prime Minister Boris Johnson's plan for a new law that would break his EU divorce treaty.
The contentious legislation, unveiled last week, would override the divorce deal the UK struck with the EU last year in several key areas related to Northern Ireland.
"The Brexit vote should ensure volatility for the pound and FTSE," noted Joshua Mahony, senior market analyst at IG trading group.
Sterling was up slightly against both the dollar and the euro, although it was far from making up the 3.6 percent it shed last week on Brexit concerns.
- No Washington deal in sight -
While major deals like Oracle's proposal to serve as Tiktok's "trusted technology provider" -- after a mooted sale to Microsoft fell through -- have proven a shot in the arm for markets, politics offered less for investors to celebrate.
"The market doesn't seem to be holding out much hope right now" that Washington will agree on a new round of stimulus to fight the economic impact of the coronavirus before November's elections, Briefing.com analyst Patrick O'Hare commented.
Some reassurance could come from a Fed meeting next week, with policymakers likely to issue "a reminder that it stands ready to provide more policy support if necessary," he said.
Markets will be eyeing the central bank's economic forecasts and "looking for details on the recent monetary policy shift... aimed at prioritising the recovery in the labor markets over inflation," Schwab analysts wrote.
- Key figures around 2050 GMT -
New York - Dow Jones: UP 1.2 percent at 27,993.33 (close)
New York - S&P 500: UP 1.3 percent at 3,383.54 (close)
New York - Nasdaq: UP 1.9 percent at 11,056.65 (close)
London - FTSE 100: DOWN 0.1 percent at 6,026.25 (close)
Frankfurt - DAX 30: DOWN 0.1 percent at 13,193.66 (close)
Paris - CAC 40: UP 0.4 percent at 5,051.88 (close)
EURO STOXX 50: FLAT at 3,316.79 (close)
Tokyo - Nikkei 225: UP 0.7 percent at 23,559.30 (close)
Hong Kong - Hang Seng: UP 0.6 percent at 24,640.28 (close)
Shanghai - Composite: UP 0.6 percent at 3,278.81 (close)
Pound/dollar: UP at $1.2845 from $1.2796 at 2100 GMT on Friday
Euro/pound: DOWN at 92.35 pence from 92.58 pence
Euro/dollar: UP at $1.1862 from $1.1846
Dollar/yen: DOWN at 105.73 yen from 106.16 yen
West Texas Intermediate: DOWN 0.2 percent at $37.26 per barrel
Brent North Sea crude: DOWN 0.6 percent at $39.83 per barrel