ORLANDO, Florida, June 18 (Reuters) - The Bank of Japan

is taking a more cautious approach to reducing its balance

sheet, meaning Japanese capital invested overseas is less likely

to be coming home anytime soon.

In the face of heightened economic uncertainty and recent

volatility at the long end of the Japanese Government Bond

curve, the BOJ announced on Tuesday that it will halve the rate

of its balance sheet rundown in fiscal year 2026 to 200 billion

yen a quarter.

The central bank began gradually shrinking its bloated

balance sheet 18 months ago and last August began an even more

gradual interest rate-raising cycle, representing a historic

shift after years of maintaining ultra-low and even negative

nominal rates.

All else being equal, this modest tightening would be

expected to narrow the yield gap between Japanese and foreign

bonds, making JGBs more attractive to domestic and foreign

investors while also strengthening the yen.

So why hasn't Japanese capital been coming home? In part,

because Japan's real interest rates and bond yields remain

deeply negative, and the latest BOJ move suggests this is likely

to remain the case for the foreseeable future.

The prospect of Japanese real returns staying deeply

negative is enhanced by current inflation dynamics. Inflation in

Japan is the highest in two years by some measures and may prove

sticky if Middle East tensions continue to put upward pressure

on oil prices. Japan imports around 90% of its energy and almost

all of its oil.

Japan's yield curve could also potentially flatten from its

recent historically steep levels if the BOJ's decision caps or

lowers long-end yields. And the curve will flatten further if

the BOJ continues to 'normalize' interest rates - something BOJ

Governor Kazuo Ueda insists is still on the table, although

markets think the central bank is on hold until next year.

MARKET MUSCLE

Either way, a flatter yield curve won't be particularly

appealing to Japanese investors who may be considering pulling

money out of U.S. or European markets. And there is a lot of

money to repatriate, meaning even marginal shifts in Japanese

investors' positioning could be meaningful.

While Japan is no longer the world's largest creditor

nation, having recently lost the crown to Germany after holding

it for more than three decades, it still has plenty of financial

muscle with a net $3.5 trillion in overseas stocks and bonds,

the highest total ever.

Analysts at Deutsche Bank estimate that Japanese life

insurers and pension funds hold more than $2 trillion in foreign

assets, around 30% of their total assets.

What would prompt Japanese investors to repatriate? In a

deep dive on the topic last month, JP Morgan analysts said

several stars would have to align, namely a sustainable rise in

long-term Japanese interest rates, an improvement in the

country's public finances, and steady yen appreciation against

the dollar.

That's a tall order. But if this were to materialize, and

banks and other depositary institutions reverted to

pre-'Abenomics' asset allocation ratios of 82% domestic bonds

and 13% foreign securities, repatriation flows from these

institutions alone could amount to as much as 70 trillion yen.

That's just under $500 billion at current exchange rates.

That's not JP Morgan's base case though, certainly not in

the near term. But over the long term, they think some reversal

of the flow of capital from JGBs into U.S. bonds over the last

decade or more is "plausible".

The BOJ's decision on Tuesday probably makes the prospect of

any significant capital shift less plausible, though, at least

for now.

(The opinions expressed here are those of the author,

a columnist for Reuters)

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(By Jamie McGeever; Editing by)