Signs that a majority of the US Supreme Court was sceptical about the legality behind a swath of President Donald Trump's sweeping tariffs also provided a little support.

Trader sentiment crept back after Wednesday's selloff that came on the back of growing worries that the tech-fuelled AI rally that has characterised markets this year has led to a bubble that could soon pop.

The rush for cover -- which tracked big losses on Wall Street -- hammered some regional giants, including Japanese tech investor SoftBank and South Korean chipmakers Samsung and SK hynix.

However, New York investors enjoyed a much happier Wednesday after figures from payrolls firm ADP showed US private sector employment jumped far more than expected last month, having surprisingly fallen the month before.

That came as a separate report indicated that activity in the crucial services industry grew far more than estimates suggested.

The jobs data release is likely to attract extra attention because it is one of the few economic indicators to come out in recent weeks owing to the US government shutdown.

Asia followed suit after Wall Street's advance, which was also helped by upbeat earnings.

Tokyo and Seoul were both well up, although still some way from clawing back all of Wednesday's losses.

Hong Kong, Shanghai, Sydney, Singapore, Taipei, Mumbai, Manila, Bangkok and Jakarta also rose.

London opened on the front foot but Paris and Frankfurt dipped.

Still, there is some concern that valuations have run a little too high on the back of the AI frenzy, which has pushed some firms to records -- with US chip titan Nvidia topping a $5 trillion valuation.

"Valuation concerns have intensified as the (S&P 500) index has climbed higher throughout the year," said IG market analyst Fabien Yip.

"Investors are questioning whether current price levels can be sustained, particularly on stocks boosted by the AI boom if interest rates remain elevated for longer than expected."

Investors were keeping a keen eye on developments in Washington after a majority of Supreme Court justices queried Trump's ability to impose his tariffs, which have raked in billions of dollars in customs revenue.

The nine justices are considering Trump's use of emergency powers to impose "reciprocal" tariffs on nearly every US trade partner, as well as levies targeting Mexico, Canada and China over their alleged roles in illicit drug flows.

Several conservative justices, along with the three liberals, questioned at a hearing on Wednesday whether the International Emergency Economic Powers Act that Trump invoked confers the authority to impose tariffs.

"The statute doesn't use the word tariffs," said Chief Justice John Roberts, and imposing tariffs is equivalent to taxation, which has always been a "core power of Congress".

The justices sought to clarify whether Congress has to give clear authorisation for policies with significant economic or political consequences.

Justice Sonia Sotomayor, a liberal, noted that the power to impose taxes is a "congressional power, not a presidential power".

"You want to say tariffs are not taxes, but that's exactly what they are," Sotomayor said.

Still, lawyers noted that if the top court finds Trump's global tariffs illegal, the government can tap other laws to temporarily impose up to 15 percent duties while pursuing pathways for more lasting levies.

- Key figures at around 0815 GMT -

Tokyo - Nikkei 225: UP 1.3 percent at 50,883.68 (close)

Hong Kong - Hang Seng Index: UP 2.1 percent at 26,485.90 (close)

Shanghai - Composite: UP 1.0 percent at 4,007.76 (close)

London - FTSE 100: UP 0.1 percent at 9,784.10

Euro/dollar: UP at $1.1510 from $1.1488 on Wednesday

Pound/dollar: UP at $1.3062 from $1.3048

Dollar/yen: DOWN at 153.80 yen from 154.13 yen

Euro/pound: DOWN at 88.12 pence from 88.40 pence

West Texas Intermediate: UP 0.5 percent at $59.87 per barrel

Brent North Sea Crude: UP 0.4 percent at $63.77 per barrel

New York - Dow: UP 0.5 percent at 47,311.00 (close)

dan/pbt

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