(Reuters) -The hefty weight of tech megacaps, a suspense-packed OPEC meeting at the weekend and more pain for consumers and businesses Down Under – these are just some of the topics preoccupying markets as they approach the halfway point of 2023.

Here’s a look at the week ahead in markets from Kevin Buckland in Tokyo; Ira Iosebashvili in New York and Dhara Ranasinghe, Karin Strohecker and Amanda Cooper in London.

1/THE NARROWEST RALLY THIS CENTURY

Some investors are growing concerned about how gains in the S&P 500 have become increasingly concentrated in a handful of megacap stocks.

The combined weight of five stocks – Apple, Microsoft, Google-parent Alphabet, Amazon and Nvidia – now accounts for 25% of the S&P 500’s market value, a trend recently supercharged by the AI buzz. Data from Deutsche Bank shows the equal-weighted S&P 500 index, a barometer of the average stock, trailing the S&P 500 by its biggest margin since 1999.

A rally driven by a handful of stocks raises questions about the health of the broader market and risks igniting volatility if investors ditch those megacap holdings.

2/FIRST IN, FIRST OUT

Emerging market central banks were quick to tighten policy in early 2021 when price pressures accelerated, front-running major developed central banks, including the Fed. Now they appear to be once again first out of the starting blocks as rate cuts move higher up the agenda.

Hungary became the first European bank to lower rates in May, following Uruguay, which kicked off the Latin American rate-cut cycle in April while Sri Lanka stunned markets with a 250-basis point rate cut on June 1.

But the picture is mixed: Polish policymakers are seen holding rates at 6.75% on Tuesday even if expectations are rising for a cut later in the year. Markets might have to wait until 2024 for India, where the next decision is due on Thursday. Russia is expected to keep its rate at 7.5% on Friday.

3/A CRUDE INVITATION

The Organization of the Petroleum Exporting Countries and partners agreed on Sunday to extend a set of production cuts into 2024. The event draws in throngs of reporters from all around the world, who jostle for position at the bottom of several flights of stairs at the OPEC secretariat that they race up to get into the pre-meeting press scrum.

Reading the runes was already tricky and Saudi Arabia, the group’s biggest exporter, unexpectedly delivered a deep cut to its own output. Saudi Energy Minister Prince Abdulaziz told a news conference the reduction was “a Saudi lollipop”. “We wanted to ice the cake. We always want to add suspense,” he said.

Adding to the suspense in the run-up to the weekend, the group banned several major news organisations from attending the press conference, including Reuters and Bloomberg.

The price of oil rose as much as 3.4% overnight to a high of $78.73 a barrel. But despite OPEC+’s best efforts, it’s still worth roughly half what it was in March 2022, after Russia invaded Ukraine.

4/INTERVENTION WATCH

The yen has fallen over 5% since early March to six-month lows against a resilient dollar.

It’s enough to make Japanese officials uneasy, with top currency diplomat Masato Kanda warning that Japan will closely watch currency moves and won’t rule out any options.

Currency intervention is viewed as a distant prospect, but traders will likely pay attention to policymaker comments in coming days after officials from the finance ministry, BOJ and Japan’s financial watchdog met on Tuesday. Such meetings can be a prelude to further action.

And it’s not just Japan traders on intervention watch. Sweden’s crown is at its weakest against the dollar and euro in over a decade, adding to inflationary pressures. A weak currency is a problem, but intervention would be a last resort, says central bank Deputy Governor Per Jansson.

Such resolve could well be put to the test.

5/RBA BRINGS THE PAIN   

    The Reserve Bank of Australia says the inflation fight is far from won, and the public should brace itself for more pain.

    That could be as soon as the next meeting on Tuesday, with markets laying about 30% odds for a hike.

    The economy had been showing signs of cooling until this week, when a reading of consumer prices jumped much more than forecast for April, sending stocks to a two-month trough.

    Rates are already at an 11-year peak after a surprise hike last month, which RBA governor Philip Lowe justified by saying he wanted to send a clear message to households and businesses that the central bank will do whatever it takes.

    Policymakers need to keep an eye on top trading partner China too, where a sputtering post-pandemic recovery risks eroding Australian ore and energy exports.

(Compiled by Amanda Cooper; Editing by Edwina Gibbs)

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