[September 29, 2026 Morning Edition] The shock of falling US memory stocks and 5.23% interest rates. Defensive strategies to protect semiconductor stocks in the Tokyo …
We have reached a notable morning that serves as the ex-dividend and ex-rights date.
The US market last night saw the three major indices all lose momentum as a surge in long-term US interest rates and rising oil prices due to geopolitical risks weighed on the stock market.
The Tokyo market today is expected to have a very difficult start, receiving a double punch from the downward pressure on the Nikkei Average of over 300 yen due to the ex-dividend date, as well as the decline in US high-tech and memory stocks.
I will provide a detailed dissection of the structural changes that occurred in the US market last night and present how to navigate today’s trading.
■ Summary of last night’s US market: The double punch of the 5.23% US 10-year Treasury yield and rising oil prices
In the US stock market last night, the buying momentum from the end of the previous week completely converged, and profit-taking selling became dominant.
The Dow Jones Industrial Average closed at $51,482, down $347 from the previous day (-0.7%), the S&P 500 index closed at 7,684, down 60 points (-0.8%), and the Nasdaq Composite Index closed at 26,820, down 248 points (-0.9%).
The factor pushing the market down was the sharp rise in the US 10-year Treasury yield.
The US 10-year Treasury yield temporarily rose to 5.23%, hovering at its highest level since 2007.
Oil prices rose due to uncertainty over negotiations surrounding the Strait of Hormuz, and with inflation concerns reignited, a very unpleasant market environment was formed where both oil prices and interest rates are rising simultaneously.
In an environment where interest rates remain high above 5.2%, the relative attractiveness of stocks, especially high-valuation high-tech stocks, decreases, and pressure for valuation correction intensifies.
Following the reaction to hitting new highs at the end of last week, the movement of investors reducing their positions became clear.
■ Light and shadow of US stocks: Nvidia’s lone struggle and the devastation of the memory sector
What is most noteworthy about the US stock market last night is the extreme division between stocks seen while the SOX index, composed of major semiconductor stocks, fell 1.6%.
The only savior in the semiconductor sector was Nvidia. The company’s stock price rose 1.7%. The background to this is the announcement of a powerful shareholder return policy to expand its share buyback program by $15 billion.
However, this rise is merely a buyback based on individual factors and does not indicate buying interest in the sector as a whole.
On the other hand, memory and storage-related stocks were exposed to devastating selling pressure.
Led by Micron Technology, which fell 2.6%, AMD fell 3.6%, SanDisk fell 3.7%, and SK Hynix ADR fell 5.0%, all plunging across the board.
Furthermore, DRAM-related ETFs also recorded a decline of about 5%, and Intel and Arm Holdings were also forced into a sluggish performance.
In addition, selling spread to large-cap high-tech stocks in general. Meta Platforms continued to fall significantly, down 4% following the end of the previous week.
It was reported that they had poached management from database giant MongoDB, which became a topic of conversation, but MongoDB itself suffered from market disappointment and plummeted 18%.
The sense of caution drifting throughout the high-tech sector is extremely strong.
■ Spillover effects to the Tokyo market and the reality of supply and demand
This movement in the US market provides extremely severe implications for the Tokyo market today.
First, the sharp drop in US memory-related stocks puts major Japanese semiconductor manufacturing equipment and materials companies such as Tokyo Electron, Advantest, and Kioxia Holdings in the direct line of fire.
The fact that Nvidia’s stock price was maintained provides psychological support, but that is due to individual supply and demand factors such as share buybacks.
With concerns about deteriorating supply and demand in the memory market as a whole emerging, it is impossible to expect a broad rise in Japanese manufacturing equipment stocks.
Second is the balance between exchange rates and interest rates. Currently, the dollar-yen is hovering in the low 157 yen range, which at first glance appears to be a tailwind for export companies.
However, in a phase where the US 10-year Treasury yield is at a high level of 5.23%, the downward pressure on global stock valuations due to high interest rates completely cancels out the profit-boosting effect of the weak yen.
The simple logic of buying Japanese stocks because of the weak yen no longer holds up in the face of current high US interest rates.
■ Today’s monitoring targets and practical risk management
In today’s trading, the key assets to watch most closely are the trends of Micron Technology and the behavior of major Japanese semiconductor stocks in response to them.
Micron has its earnings announcement coming up tomorrow, the 30th.
It was sold off 2.6% last night due to pre-earnings caution, but if Tokyo Electron or Advantest break below their lows along with ex-dividend adjustments in the Tokyo market today, the risk that the trend of the entire semiconductor sector will shift one step lower will increase.
The absolute rule for today’s maneuvering is not to easily buy into the market (jumping catch) immediately after the opening bell.
On a day that is an ex-dividend date, a turning point for supply and demand, with the decline in US high-tech and memory stocks overlapping, today is a day when the clearing of buyer positions is likely to accelerate.
This is not a situation to aggressively chase profits. Keeping your position lot size smaller than usual and maintaining a higher cash ratio, while first observing the reactions of the European and American markets from this evening through the night, is the wisest choice to protect your valuable assets.
When market volatility is high, taking a break is also a sound strategy.
Today, let’s maintain a thorough defensive stance and calmly assess the shifts in market trends. Let’s continue to prioritize strict risk management and approach the market with a safe, cautious mindset this week.
*This post is intended for informational purposes and chart analysis commentary, and does not solicit or instruct any specific investment actions. Please make final investment decisions based on your own judgment and responsibility.