* S&P 500 down slightly in early trading

* U.S. dollar up against the yen, at 38-year high

* Investors on alert for yen intervention

NEW YORK, June 26 (Reuters) -

The dollar hit a fresh 38-year high against the Japanese yen on Wednesday, with investor speculation high that Japanese authorities could intervene to strengthen the currency, while global stock indexes were mostly lower.

Japan's

top currency

diplomat, Masato Kanda, said Japanese authorities were "seriously concerned and on high alert" about the yen's rapid decline.

In April, a fall to 160.245 per dollar was enough to prompt Tokyo to spend roughly 9.8 trillion yen to support the yen.

The latest slide follows the Bank of Japan's (BOJ) decision this month to hold off on reducing bond-buying stimulus until its July meeting.

The dollar was last up 0.6% at 160.62 yen.

The dollar index, which measures the greenback against a basket of currencies, gained 0.27% to 105.95, with the euro down 0.21% at $1.0689.

On Wall Street

, the Dow and S&P 500 eased as the Nasdaq gained.

Artificial intelligence

chip leader

Nvidia was down slightly. A sell-off in the previous session wiped $430 billion off its market value.

The Dow Jones Industrial Average fell 128.53 points, or 0.33%, to 38,981.88, the S&P 500 lost 10.58 points, or 0.19%, to 5,458.72 and the Nasdaq Composite gained 24.56 points, or 0.13%, to 17,740.55.

MSCI's gauge of stocks across the globe fell 1.82 points, or 0.23%, to 801.95. The STOXX 600 index fell 0.55%.

Investors are looking for clues on how soon the Federal Reserve could begin to cut interest rates.

Fed officials have urged patience on interest rate cuts. Fed Governor Michelle Bowman has reiterated her view that holding the policy rate steady "for some time" would probably be enough to bring inflation under control.

Investors await Friday's release of the U.S. personal consumption expenditures (PCE) price index, the Fed's preferred inflation measure, with economists polled by Reuters expecting the annual growth to ease to 2.6% in May.

U.S. Treasury yields rose amid a pick up in inflation in other countries.

On Wednesday, Australia consumer inflation accelerated to a six-month high in May.

The yield on benchmark U.S. 10-year notes rose 7.4 basis points to 4.312%, from 4.238% late on Tuesday.

U.S. crude lost 0.4% to $80.49 a barrel and Brent fell to $84.78 per barrel, down 0.27% on the day.

(Additional reporting by Samuel Indyk and Ankur Banerjee; Editing by Shri Navaratnam, Himani Sarkar, Alex Richardson and Gareth Jones)