For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window.

Updates before markets open

By Shashwat Chauhan and Kanchana Chakravarty

May 29 (Reuters) - Wall Street's main indexes were on track for a higher open on Thursday after a federal court ruled against most of U.S. President Donald Trump's tariffs and AI bellwether Nvidia reported a 69% surge in quarterly sales, lifting sentiment.

Nvidia NVDA.O jumped 5.6% in premarket trading after reporting higher-than-expected quarterly sales growth, driven by customers stockpiling AI chips ahead of U.S. export restrictions on China.

The company, however, warned that the new curbs are expected to cut $8 billion from its current-quarter sales.

"We're in a secular growth trajectory here for AI, AI investment, and everything seems to be lining up for the next kind of multi-quarter expansion across AI," said David Russell, global head of market strategy at TradeStation.

Other chipmakers rose in the wake of Nvidia's results, with Advanced Micro Devices AMD.O gaining 2.8%. The VanEck Semiconductor ETF SMH.O advanced 2.7%.

Global risk appetite was boosted after a U.S. court invalidated with immediate effect most of Trump's sweeping levies imposed since January, but did not address some industry-specific tariffs on automobiles, steel and aluminum.

"Even if the ruling is upheld, the administration will have alternative routes to implement tariffs. But these will be slower and more targeted, as opposed to the current sweeping approach," said Lizzy Galbraith, senior political economist at Aberdeen.

The ruling can be appealed in the U.S. Court of Appeals for the Federal Circuit in Washington, D.C., and potentially the U.S. Supreme Court.

Kevin Hassett, the White House economic adviser, said three trade deals were nearly done and he expected more despite the judgment.

At 08:31 a.m. ET, Dow E-minis YMcv1 were up 116 points, or 0.28%, S&P 500 E-minis EScv1 were up 51.5 points, or 0.87%, and Nasdaq 100 E-minis NQcv1 were up 304 points, or 1.42%.

Apple AAPL.O, which Trump threatened with tariffs last week, led gains among other megacap and growth stocks with a 2.2% jump. Meta Platforms META.O rose 1.3%, while shares of Alphabet GOOGL.O added 1.2%.

The S&P 500 is currently about 4% below an all-time high touched on February 19, rebounding from a nearly 19% decline earlier in April on easing trade tensions, strong earnings and subdued inflation data that aided risk appetite.

May has been a solid month for equities, with both the S&P 500 .SPX and the Nasdaq .IXIC on pace for their best monthly performances since November 2023.

A second reading from the Commerce Department showed gross domestic product contracted 0.2% in the first quarter. Economists polled by Reuters had forecast a 0.3% contraction.

At least five Fed policymakers including Fed Board Governor Adriana Kugler are scheduled to speak through the day.

In other earnings, Best Buy BBY.N dropped 2.5% after the electronics retailer lowered its annual comparable sales and profit forecasts amid concerns that U.S. tariffs would weigh on consumer demand for big-ticket items.

HP Inc HPQ.N shed 9.5% after the PC-maker cut its annual profit forecast.

(Reporting by Shashwat Chauhan and Kanchana Chakravarty in Benglauru; Editing by Sherry Jacob-Phillips, Maju Samuel and Pooja Desai)

((Shashwat.Chauhan@thomsonreuters.com; Kanchana.Chakravarty@thomsonreuters.com))