SINGAPORE (Reuters) -Asian equities slipped on Thursday, weighed down by weaker-than-expected Chinese activity data and a plunge in copper prices, while the yen firmed after the Bank of Japan raised its inflation forecast for the fiscal year and held rates steady.

The revised forecast suggested cautious optimism that Japan's trade deal with the U.S. would help the economy avert a steep downturn and set the BOJ on a path to hike interest rates later in the year.

The yen firmed 0.6% to 148.62 per U.S. dollar immediately after the central bank maintained short-term interest rates at 0.5%, as expected, by a unanimous vote.

Japanese shares showed little reaction to the decision and were last up 0.9%.

In an action-packed 24 hours, investors were also digesting a trade deal between the U.S. and South Korea, a Federal Reserve decision to hold rates steady and strong earnings from megacap tech firms.

Nasdaq futures surged 1.2% after better-than-expected earnings from Microsoft and Meta Platforms. S&P 500 futures advanced 0.8%, while the U.S. dollar held steady after hitting a two-month high. [FRX/]

Both tech companies' earnings reports "have shot the lights out", reporting higher revenue from cloud computing and artificial intelligence-enabled ad targeting respectively, said Tony Sycamore, a market analyst at IG in Sydney.

MSCI's broadest index of Asia-Pacific shares outside Japan eased 0.7%, though it was still on track for its fourth consecutive monthly gain in July.

Stocks in Hong Kong and China led declines after official PMI gauges showed weaker-than-expected economic activity during July.

The Federal Reserve's rate-setting committee voted 9-2 on Wednesday to hold interest rates steady for the fifth consecutive meeting, with two Fed governors dissenting for the first time in more than three decades.

Fed Chair Jerome Powell's comments after the decision undercut confidence that borrowing costs would begin to fall in September.

The dollar index was at 98.812, just shy of the two-month high of 99.987 it touched on Wednesday. The index is set to clock a 3.1% gain for the month, its first in 2025.

"Although the Federal Reserve decided to keep rates steady at its recent rate setting decision, the chance of rate cuts at upcoming meetings remain live as they balance softening economic data with the potential for persistent inflation," said Manusha Samaraweera, fixed income investment director at Capital Group.

U.S. gross domestic product growth rebounded more than expected in the second quarter, but the details of the report painted a picture of an economy that was losing steam and plagued by uncertainty from President Donald Trump's protectionist trade policies.

The Korean won appreciated 0.3% after Trump said the U.S. will charge a 15% tariff on imports from South Korea, which will in return invest $350 billion in U.S. projects and purchase $100 billion in U.S. energy products.

The announcement is the latest in a series of trade policy deals rushed out before an August 1 deadline to avert the imposition of the April 2 "Liberation Day" tariffs.

Trump's tariff blitz cast a shadow on global markets, with negotiations on trade with India still under way after Trump earlier announced that the U.S. will impose a 25% tariff on goods imported from the country.

Meanwhile, copper futures plunged 19% after Trump said the U.S. will impose a 50% tariff on copper pipes and wiring, as the details of the levy fell short of the sweeping restrictions expected and left out copper input materials such as ores, concentrates and cathodes.

Oil prices were little changed on Thursday, with Brent crude futures for September delivery, which are set to expire on Thursday, down 0.19% at $73.1 a barrel, while U.S. West Texas Intermediate crude for September was flat at $70.01 a barrel.

The more active Brent October contract eased 0.14% to $72.37 per barrel.