事態が急変しました…AI・半導体相場に〇〇年以来の異常事態！｜今、私たち個人投資家は何をするべきなのか【元ゴールドマンサックスが徹底解説】

Summary

The presenter argues that investors should prepare not only for a conventional stock-market crash, but also for an “invisible crash”: inflation and currency depreciation that reduce the purchasing power of cash even while nominal stock prices rise. This is presented as a risk scenario, not a definite forecast.

The proposed driver is competition for a finite pool of global savings between two large borrowers: the U.S. government and U.S. technology companies investing heavily in AI infrastructure. If borrowing demand keeps long-term interest rates high, the presenter says, government debt costs and Big Tech financing costs could both rise. If the U.S. instead caps yields through monetary intervention, cash and deposit holders could bear the cost through diminished purchasing power.

Key figures cited

The figures below are claims made in the video, mostly dated August–October 2026. The auto-generated subtitles may contain errors.

• The U.S. 10-year Treasury yield is said to have exceeded 5.2%, its highest level since 2007. JPMorgan CEO Jamie Dimon is quoted as warning that 6% rates would be more painful than a move from 4% to 5%, while emphasizing that this was not a prediction.
• U.S. Treasury buybacks allegedly doubled in August 2026 and tripled in September 2026, with limited lasting effect on yields.
• U.S. federal debt is said to have passed $40 trillion on August 18, 2026, after reaching $38 trillion in March and $39 trillion five months later—roughly $1 trillion of additional debt every five months.
• U.S. interest costs are put at $970 billion, or 3.2% of GDP, for FY2025—up from 1.6% of GDP in FY2020 and more than the defense budget. The video says FY2026 costs could exceed $1 trillion.
• Big Tech debt issuance is described as averaging $28 billion annually in 2020–24, rising to $121 billion in 2025 and about $220 billion by early August 2026. A $400 billion 2026 total is cited when related issuers are included. The transcript’s specific Amazon issuance figure is unclear.
• AI-related capital expenditure is estimated at about 2% of U.S. GDP in 2026, with some forecasts averaging 3.6% in the early 2030s.
• The video says that another one-percentage-point increase in rates could add roughly $300 billion annually to interest costs on about $30 trillion of debt subject to refinancing.
• A cited Congressional Budget Office scenario projects U.S. debt at 175% of GDP by 2056, or 222% if rates remain high.
• Japan’s 10-year government bond yield is given as 2.93% on October 16, 2026, with the Bank of Japan policy rate at 1.25%.
• For a Japanese mortgage with ¥30 million remaining over 20 years, the presenter estimates that a one-percentage-point increase in the variable rate could add about ¥3 million in total interest.

Historical examples

• U.S. in the 1940s: The video says the Federal Reserve capped short-term Treasury yields at 0.375% and long-term yields at 2.5% from 1942. The Dow fell from around 150 in 1940 to 92.92 on April 28, 1942, then rose to 212.5 by May 1946—about 2.3 times its low. U.S. CPI reportedly rose 72% from 1940 to 1948, substantially reducing the dollar’s purchasing power. The presenter’s point is that cash holders and wage earners, rather than asset holders, bore much of the inflationary cost.
• Japan’s yield-curve-control era: From September 2016 to March 2024, the Nikkei is described as rising from the 16,000s to around 40,000, while USD/JPY moved from about ¥101 to ¥151 per dollar. The presenter uses this as an example of stocks rising while the yen weakened.
• The video also says that in March 2026, amid the Iran war, the S&P 500 fell about 10% and the Nikkei about 13.2%. The broader caution is that intending to buy a crash and actually buying during one are different things.

Investment framework and implications

• Trace the chain behind economic news. For example, high U.S. rates may support the dollar; a stronger dollar can pressure the yen; yen weakness can sustain Japanese import inflation; and persistent inflation may encourage further Bank of Japan rate increases. The presenter says this chain can help investors identify industries that may benefit or face pressure.
• Map holdings by their exposure to the financing conflict. The presenter frames deposits and cash as potentially exposed to inflation or currency depreciation, while equity funds may own companies that benefit from—or are hurt by—the eventual interest-rate policy response.
• Watch for signs of yield caps or financial repression. Suggested indicators include the size and frequency of government-bond buybacks and changes in central-bank asset holdings.
• Assess portfolio resilience, not just expected returns. The video urges investors to consider how much a portfolio could fall and still meet their needs, particularly if withdrawals begin during a downturn.
• Account for withdrawal timing. A decline during the saving phase is not equivalent to the same decline after retirement withdrawals begin, because selling assets to fund spending can lock in losses.
• Review household debt alongside investments. Rising Japanese interest rates may increase mortgage costs before savings plans have time to grow.
• Treat dollar-cost averaging as a stabilizing tool, not a complete life or wealth strategy. The presenter supports regular saving but argues that it does not, by itself, create a step-change in income, skills, or financial options. He encourages deliberate learning and decision-making rather than simply increasing contributions.
• Avoid assuming there is a single prescribed portfolio. The presenter does not give a specific buy or sell recommendation and says investors need to assess their own accounts, time horizons, and risk capacity.

Possible U.S. policy responses

The presenter outlines four options for a heavily indebted government:

1. Cut spending to reduce borrowing, though this may be politically difficult.
2. Raise taxes, while noting that excessive tax rates can discourage work or drive activity elsewhere.
3. Default, which the presenter considers highly damaging to the global financial system.
4. Use monetary policy to hold down yields—described as financial repression or a yield cap—potentially reducing the real value of debt through inflation.

The video presents the fourth option as one that could simultaneously ease government borrowing costs and lower Big Tech’s financing costs. It suggests the U.S. may be moving in that direction, but does not claim to know when or in what form.

Assets, markets, sectors, and instruments mentioned

• Equity indexes: S&P 500, Nikkei 225, Dow Jones Industrial Average
• Companies: Microsoft, Alphabet, Meta, Amazon, Oracle
• Other assets and instruments: U.S. Treasuries, Japanese government bonds, developed-country bond funds, deposits and cash, U.S. dollar, Japanese yen, gold, real estate, index funds, NISA investment accounts, and mortgages
• Sectors: AI and data centers, technology, Japanese financials, real estate, and power and utilities

No individual stock tickers or specific gold, ETF, or bond products are recommended.

Disclosures and cautions

The video’s metadata says the channel discusses publicly available information and the presenter’s views, not investment advice. Investing involves risk, and decisions are the viewer’s responsibility. It also says the stock commentary is not intended as a short-term trading recommendation. The presenter makes no specific portfolio recommendation in the subtitles.

Presenters and sources mentioned

The auto-generated subtitles identify the presenter as “Chan.” The channel is おーちゃん【元外銀マン】, and the presenter refers to experience at Goldman Sachs.

Sources or figures cited include the U.S. Federal Reserve, U.S. Treasury, Congressional Budget Office, Bank of Japan, S&P, Jamie Dimon/JPMorgan, and Milton Friedman.