The Week Interest Rates Became 'Personal'—Record for the Second Week of October 2026
This week (October 5–9, 2026) was a week where interest rate data for all five business days was available. While all four major countries maintained a normal yield curve and there was no clear direction, it was a week that left an impression regarding the ‘time lag’ that can gradually affect daily decision-making.
Interest Rate Trends This Week (10/5–10/9)
Japan
The policy rate (ON) remained unchanged throughout the week at 1.227%. The 10-year bond moved slightly from 3.097% at the start of the week to hover around 3.089% as of the weekend on 10/9. The 30-year bond fluctuated in a range of 4.136% to 4.168%. The slope of the curve (30-year minus ON) remained between approximately 2.91% and 2.94%, maintaining the steepest slope among major countries.
United States
The ON rate was stable at 3.88%. The 10-year bond rose early in the week, peaking at 5.31% on 10/7, before being pushed back slightly to 5.27% on 10/8 and 5.28% on 10/9. The 30-year bond also fluctuated slightly within a range of 5.61% to 5.67%.
Japan-US Spread
The Japan-US 10-year bond spread widened from 2.143% as of 10/5 to 2.207% on 10/7, then narrowed to 2.159% on 10/8, and ended the week at 2.191% on 10/9. A spread of over 2% continues, and the structural background for yen depreciation pressure remains unchanged.
Europe and the UK
The EU 10-year bond showed little direction, ranging between 3.46% and 3.54%. The UK saw a slight rise from 10/6 to 10/8 before falling to 5.337% on 10/9. The UK 30-year bond hovered around 5.70%, remaining at a high level alongside the US.
Foreign Exchange and Real Estate
Regarding foreign exchange (FX), the latest data is as of 2026-10-02, and since data for the target week is not included, I will refrain from mentioning it this time. I will also not touch upon real estate as there is no data for the target week.
Essay: The Blind Spot Called ‘Time Lag’
Looking back at this week’s topics, one keyword remained in my mind: time lag.
Interest rates rise. That can be observed as a fact. But it is surprisingly difficult to see where and when that impact will arrive.
Monday’s post was about the ‘time lag in rent pass-through.’ The story that it takes several years for a landlord to feel the burden of variable mortgage repayments and for that to be reflected in rent. It made me realize once again that there is a long chain before the impact of rising interest rates ripples through to real estate prices.
Tuesday’s ‘six-month delay for individual government bonds (variable 10-year)’ follows the same structure. A mechanism where you wait six months to receive the benefits of a rate hike. Whether it’s a gain or a loss, many financial products in the world are designed not to react immediately. This is not a flaw in the system, but rather a buffer in the design, but I suspect many people assume it ‘has nothing to do with them’ without knowing that.
Thursday’s ‘interest rate sensitivity of auto and education loans’ was from a slightly different angle. Unsecured consumer loans reflect interest rate hikes more quickly than mortgages. Because there is no time lag, it should be easier to see, but the narrow-mindedness of ‘as long as I pay attention to housing’ creates a blind spot. I think a sense of security from knowing only half the story can sometimes be scarier than ignorance.
Friday’s ‘corporate bond costs and sources for wage increases’ was a story about an even more distant ripple effect. When a company’s procurement costs rise, it eventually cuts into the employees’ capacity for wage increases. The story of your own salary and the story of the central bank’s policy rate may seem unrelated at first glance, but they are actually located upstream and downstream on the same river.
From the perspective of a developer who designs systems every day, the sensitivity to this ‘lag between input and output’ is very similar to the feeling of writing code. When debugging asynchronous processing, you need to track ‘why the result appears at this timing.’ Cause and effect are not necessarily close in time. The financial world is the same; if this week’s interest rate fluctuations appear in rents or wages years from now, I felt it is important not to assume that the causality is ‘visible’.
Another thing that left an impression was a post on Saturday about the ‘lack of correlation between hometown tax donations and interest rates.’ It pointed out that as interest rate news increases, more people tend to associate even unrelated systems with interest rates. When the information environment is saturated, people tend to categorize things that are ‘vaguely in the same category’ together. I felt that in phases with a lot of noise, it is necessary to develop the habit of pausing to confirm, ‘Is this actually related?’
Outlook for Next Week
The Japan-US 10-year spread continues to remain stable at the 2.1–2.2% level. Since I have only been able to confirm the impact on exchange rates up to the data from 2026-10-02, I would like to check how the latest FX data is moving next week.
In terms of topics, from the latter half of this week, discussions on concrete decision-making regarding scholarship interest rate selection have emerged. From next week onward, topics centered on ‘system design’ and ‘individual choices’ may increase. In a phase where interest rates continue to rise, ‘whether you knew or didn’t know’ will result in differences in household finances over the long term. I would like to continue to carefully follow such discussions.