* Yen choppy as traders stay on intervention alert

* Oil flat, US launches effort to free ships from Strait

of Hormuz

* Busy week for earnings includes AMD, Super Micro

* Payrolls data to shape outlook for Fed policy

(Adds quote in paragraph 8, recasts with European open)

By Nell Mackenzie and Wayne Cole

LONDON/SYDNEY, May 4 (Reuters) - Global stock markets

made gains on Monday as investors were focused on developments

in the Middle East conflict at the start of a week packed with

earnings and economic data.

The Japanese yen suddenly jumped in Asian trading, with the

dollar falling sharply before paring some of the

losses. Traders are on alert for intervention after Tokyo

stepped into the market to shore up the currency last week.

Iran's military warned U.S. forces on Monday not to enter

the Strait of Hormuz after President Donald Trump said the U.S.

would start helping to free ships stranded in the Gulf by the

U.S.-Israeli war on Iran.

Trump provided few details of the plan to aid ships, while

the U.S. Central Command said it would support the effort with

15,000 military personnel, more than 100 land- and sea-based

aircraft, along with warships and drones. A report from Axios

later claimed the U.S. Navy would not necessarily escort ships

through the strait.

Against this backdrop, Brent crude futures surged

over $2.50 to $110.73 per barrel, having recovered from an

initial decline during Asian trading hours, while U.S. crude

also climbed more than 2% to $104.18.

Dealers noted a bulk carrier had reported being attacked by

multiple small craft while transiting past Sirik in Iran on

Sunday, though it was not clear how many ships would try to run

through the Strait of Hormuz even with Navy protection.

"The market is being pulled in two opposing directions right

now: on one hand, geopolitical risk is pushing oil higher and

reviving inflation fears, but on the other, underlying growth

especially in the U.S., is clearly softening," said Bruno

Schneller, managing partner at Erlen Capital Management, a

multi-family office.

This combination was driving some of the big market swings

recorded in stocks, bonds and currencies, he added.

MSCI's broadest index of global shares outside Japan

rose, led by tech-heavy South Korean stocks

which returned from a holiday with a jump of over 5%.

Hong Kong's Hang Seng index gained 1.2%.

In Europe, German carmakers dampened the region's start to

the week after Trump said on Friday that Washington would raise

tariffs on European cars and trucks.

The pan-European STOXX 600 declined by 0.3% to

609.64 points after posting a modest gain last week. Most

regional bourses were muted while Germany's DAX rose

0.2%.

Trading in Europe was subdued; markets in London were closed

for a public holiday.

CENTRAL BANKS WARN OF INFLATION RISKS

As another earnings-heavy week gets underway, concerns

remained about the scale of artificial intelligence capex

investment, now at $751 billion for 2026, $80 billion above

estimates at the start of the earnings season and 83% above 2025

spending.

Companies reporting this week include Advanced Micro Devices ( AMD )

, Super Micro Computer ( SMCI ), Palantir, Walt

Disney ( DIS ) and McDonald's.

The threat of oil-driven inflation also lifted bond yields

in a challenge to equity valuations, while several major central

banks had turned hawkish on policy.

Market participants no longer expect the U.S. Federal

Reserve to lower rates this year and have priced in

interest-rate hikes from the European Central Bank and Bank of

England .

Barclays on Monday joined a growing list of brokerages to

bet on no policy easing from the Fed this year.

Data this week, including Friday's keyApril payrolls report,

could potentially shift the Fed outlook.

YEN WATCH

In global forex markets, the yen remained in the spotlight

with traders on edge over potential Japanese intervention to

boost the currency.

The dollar was recently flat at 156.93 yen, having

fallen to as low as 155.7 yen earlier, as traders smarted from

last week's Japanese intervention, which analysts thought could

have amounted to around $35 billion.

"But fundamentals remain in favour of USD/JPY, meaning

USD/JPY will sooner or later recover and force the MoF's hand

again," said Carol Kong, a currency strategist at the

Commonwealth Bank of Australia, who added that given the size of

Monday's moves, she doubted Japan had interfered.

She attributed the turbulence to choppy trading in

holiday-thinned markets.

The euro was steady at around $1.17, while

sterling inched lower to $1.3560.

In commodity markets, gold ticked lower to $4,578 an ounce

.

(Reporting by Nell Mackenzie and Wayne Cole; Additional

reporting by Ankur Bangerjee in Singapore; Editing by Thomas

Derpinghaus, Dhara Ranasinghe and)