TOKYO (AP) — Asian shares were mixed on Tuesday following a rally on Wall Street that was helped by easing oil prices.

Regional investors were still weighing the impact from last week’s joint U.S.-Japan currency intervention, analysts said.

Japan’s benchmark Nikkei 225 slipped 0.3% to 63,585.58, as the U.S. dollar inched up to 157.51 Japanese yen from 157.18 yen. The euro cost $1.1511, little changed from $1.1514. The dollar was trading at 160-yen levels before regulators stepped in to boost the yen’s value after it fell to nearly 40-year lows.

Some analysts said the effectiveness of such an intervention remains uncertain as it doesn’t address the fundamental economic reasons behind the currency fluctuations, including inflation, interest rates and the relative strengths of the economies.

“A U.S.-backed operation carries far more signaling weight than Tokyo acting alone, and the pledge of further action will give speculators pause. But any U.S. contribution will probably be constrained by size,” a report by BMI, a unit of Fitch Solutions, said.

Matthew Ryan, head of market strategy at global financial services firm Ebury, noted the latest effort could have some impact because it appears to signal a real change in monetary policy rather than just a one-time defensive move.

“This is an historic and meaningful development for the yen, which materially improves confidence in our mildly bullish call for the currency,” he said.

South Korea’s Kospi sank 1.3% to 6,174.72. Australia’s S&P/ASX 200 added 1.2% to 9,129.00. Hong Kong’s Hang Seng fell 0.5% to 25,881.99, while the Shanghai Composite gained 0.2% to 3,802.61.

Markets remain unsettled by swings for stocks of companies that make computer chips. They’ve been veering up and down for weeks on worries about whether their surging revenues because of the artificial-intelligence boom are sustainable.

On Wall Street, share prices rallied Monday after easing oil prices helped calm worries over inflation. The S&P 500 jumped 1.5% and is just 0.1% below its record set earlier this summer.

The Dow Jones Industrial Average, which measures a narrower slice of the U.S. stock market, climbed 693 points or 1.3% to an all-time high, while the Nasdaq composite leaped 2.1%.

In energy trading in Asia early Tuesday, benchmark U.S. crude gained 84 cents to $81.18 a barrel. Brent crude, the international standard, jumped $1.15 to $84.92 a barrel.

A day earlier, oil prices dropped more than 5% after U.S. President Donald Trump said over the weekend that he had decided to hold off on new strikes against Iran at the urging of allies in the region.