The Unwind Isn’t Over: Japan’s 30-Year Yield High and the Currency Tailwind for MPF Japan Equity Funds

Track 2 | Data Trading Room | 26 September 2026

On 18 September 2026, the Bank of Japan raised its policy rate to 1.25%, a 31-year high. Markets did not exhale. On 24 September, the 10-year Japanese government bond yield climbed above 3% — its first time above that level since August 1996 — and pushed to about 3.06% the following day, which pulled the yen off its lows. The 30-year yield printed an all-time record of 4.223% (that maturity has only existed since 1999). This was not a celebration of a rate hike. It was a live broadcast of a global bond sell-off.

Deutsche Bank fixed-income strategist Shoki Omori gave Reuters a line every MPF member should read carefully: “The fast-money carry trade has already been unwound; the slow-money one has not started.” The slow money, he specified, is Japanese pensions and households holding unhedged overseas assets. One of the world’s largest pools of overseas capital is still parked abroad.

For Hong Kong MPF members, this is not a Japanese curiosity. MPF Japan equity funds hold Japanese assets unhedged and priced in Hong Kong dollars — the MSCI MPF Japan Unhedged Index is literally the benchmark built for them, with the currency leg as half of the return equation. When the world’s biggest capital pool starts heading home, yen appreciation is a dividend paid to Japan equity fund holders.

1. The Macro Matrix: A Global Hiking Relay

First, read the board. This September’s hiking regime is no longer a US solo act:

The key detail is how wide the rate gap still is. The US 2-year yields 4.9035% against a BOJ policy rate of 1.25% — roughly 365 basis points of spread. The 18 September hike merely compressed carry-trade profits from 300 to 275 basis points; the business continues. That is why the yen weakened after the hike: speculators went into the meeting positioned for hawkishness, not against the yen. CFTC data for the week to 15 September showed non-commercial traders net long 120,359 yen contracts (long 237,951 against short 117,592) — a swing of roughly 109,600 contracts into net long in a single week. The 7–2 vote split and the absence of clear forward guidance disappointed them.

But the powder keg of the unwind is still full. JPMorgan estimates roughly ¥16–17 trillion (about US$103 billion) of bearish yen positions remain outstanding; a decisive break of USD/JPY below 155 could force covering and accelerate the pair toward 142–146. From 159, that is an 8–11% yen rally. Former BOJ board member Makoto Sakurai expects the central bank to raise rates roughly once a quarter, reaching 2% by around next June. The slow money’s departure is a matter of time, not probability.

The Nikkei is already sniffing it: +1.9% to 65,332.57 on hike day (18 Sept); 66,364.20 on 25 September — five straight gains, the highest close in about two weeks (the year’s high sits near 72,831). AI semiconductors are leading, but notice what matters: equities are rising while the yen has not yet rallied. The second half of the gain is still on its way.

2. Backtest and Hit Rate: The Currency Is the Second Engine

The MPF Japan benchmark (MSCI MPF Japan Unhedged Index, HKD, unhedged) shows how much the currency matters. Annual returns in recent years: -16.21% in 2022 (the year the yen collapsed through 150), +20.83% in 2023, +8.11% in 2024, +25.30% in 2025, and already +17.13% year-to-date through May 2026, with a three-year annualised 20.68%. This index records both equity prices and the exchange rate: a weak yen eats returns; a strong yen multiplies them.

There was a rehearsal this May: USD/JPY plunged from 157.70 to 155.03 in a single session — nearly 2% of yen appreciation in one day, the textbook signature of a carry-trade unwind. The lesson: unwinds never arrive gradually; they arrive all at once. That episode was reversed within a day by hawkish Fed repricing — but this time the structure is different. The BOJ has committed to keep hiking, and the Ministry of Finance has raised its borrowing assumptions to 3.8%. The fundamentals of the unwind are being reinforced layer by layer.

Hit-rate assessment: JPMorgan’s 155 trigger sits just ~2.5% below current levels, and with Fed funds futures pricing more than 90 basis points of further tightening this cycle, the cost of global carry funding is rising from the US side too. In other words, unwind pressure is not coming from the yen alone. The combination of yen appreciation plus Japanese equity strength has historically been the sweet spot for excess returns in unhedged Japan funds.

In Hong Kong dollar terms: on a HK$100,000 Japan equity allocation, an 8–11% yen rally translates to roughly HK$8,000–11,000 of pure currency gain — before any equity upside. That is the arithmetic of the second engine.

3. The Switching Blueprint: Writing the Currency Gain into the Allocation

(Illustrative sandbox, not personal investment advice. All percentages refer to constituent-fund allocation.)

The real instruments inside the MPF framework are each scheme’s Japanese equity constituent funds (benchmarked to the unhedged index above) and global/Hong Kong bond constituent funds. A reference sandbox:

Base allocation (age 40, medium risk)
– Hong Kong equity fund 25%
– US equity fund 35%
– Japan equity fund 5%
– Asia-Pacific / global equity fund 15%
– Hong Kong bond fund 20%

Unwind-tilted version
– Japan equity fund: 5% → 10% (+5 percentage points, funded from US equity 35% → 30%)
– Hong Kong bond fund: hold at 20%, but favour short duration — the global bond market is suffering its most violent sell-off since 2004 (US 30-year 5.48%, Japan 30-year at records); long duration is this cycle’s biggest casualty
– Execute in two tranches: 2.5 percentage points each, roughly a week apart

Why fund it from US equities rather than Hong Kong? MPF Ratings’ 24 September estimate: US equities are MPF’s best-performing asset class so far in September, and the system is running a year-to-date return of about 7.55% — on track for a fourth consecutive positive year, with an average member balance of HK$343,242. Taking the tilt from relative strength is rebalancing discipline, not momentum chasing.

On that average balance: a 5-point Japan tilt equals HK$17,162; a 10% yen rally adds roughly HK$1,716 of pure currency gain — nearly a month of mandatory contributions (5% employee contribution on a HK$30,000 salary is HK$1,500).

Who should not follow? Members within five years of retirement whose portfolios are already on the DIS automatic de-risking path: currency moves cut both ways, and short horizons amplify sequence risk. The flip side of the unwind trade is that if USD/JPY first spikes toward 164 before reversing, unhedged Japan funds will feel the volatility before the dividend.

4. Forward-Pricing Protection: Execution Discipline under T+1/T+2

MPF switching runs on forward pricing: the fund price you see when you submit an instruction is not the price you get — your trade executes at the next (T+1/T+2) trading day’s net asset value. The signature of an unwind is a single-day spike (May’s USD/JPY drop from 157.70 to 155.03 happened inside one session). Converting a large sum in one go under forward pricing means buying and selling blind on the most volatile day of all.

The execution checklist:

1. Avoid central-bank windows: no large switching instructions on BOJ or FOMC decision days, nor the day before. The next Fed meeting is in October (futures price a 71% chance of a hike); the BOJ may hike quarterly — place tranches in the gaps between meetings.
2. Tranching is iron law: 2.5 percentage points per tranche, at least one full trading week between the two, so the first tranche’s execution price is settled before committing the second.
3. Check cut-off times: every trustee has its own daily cut-off; an instruction after cut-off rolls to the next day, adding another layer of forward-price uncertainty.
4. Mind the out-of-market gap: money in transit between funds sits outside the market — a one-day spike in either direction is missed. Tranching means half the capital is always still in the market.
5. Audit bond-side duration: if you hold a global bond fund rather than a Hong Kong bond fund, check the fact sheet’s duration figure — with the US 30-year at 5.48% and JGBs at records, long-duration funds are seeing price falls eat the yield.

One last figure: Omori said the slow money hasn’t started moving — Japanese pensions and households with unhedged overseas assets. MPF members are slow money of a different kind: forward pricing, cut-off times and transit risk mean we can never be fast. But slow has its own playbook: tranche the move, avoid the rate meetings, and write the currency gain into the allocation instead of chasing it. Unwind markets never reward the fastest. They reward whoever stands on the right side with the most discipline.