On the night of Sunday, October 18, 2026, a thread about the Nikkei average on 5ch’s “Nandemo Jikkyo G” (Live Broadcast G) board drew reactions from investors bracing for a steep continued drop on Monday. Rising bond yields at CoreWeave, the GPU-rental company that bankrolls much of the AI investment boom, were flagged as a sign of an “AI bubble bursting,” and posters holding semiconductor stocks like Kioxia reported paper losses topping 3 million yen, with some fearing it could hit 4 million yen by the next day. Still, some cooler heads argued the CoreWeave story was nothing new, and opinions diverged sharply between those sitting on NISA (tax-free investment account) gains over whether to sell, and those who’d only just started investing this year wondering how to respond.
Surely nobody's still slow enough to not have sold their NISA by now, right?
Already down 3 million yen on paper. Tomorrow it'll probably hit 4 million 😭
In 10 years you'll be in the green, trust me
is peak uninformed-investor behavior
I'm on margin though, think I'll be okay? 🥺
My condolences.
People are saying it's an AI bubble bursting because bond yields rose at CoreWeave, a company that leases out GPUs
But that's old news by now, and even if CoreWeave went bankrupt, AI investment wouldn't just stop — yet somehow the market's tanking anyway
The yield rose because bonds got dumped once interest costs started outpacing profit growth — that's not 'old news,' it's a different situation this time
What are you even implying 🥺
By the way, I just put in another market buy order for Kioxia
You're lying, right? lol
What are you buying?
I want to pick up more Fujikura and V Technology if they drop another leg
Fujikura's the one I'm watching closest
Kioxia's probably still got a lot further to dig down, so I'm leaving it alone
The question is when it ends, and how
that's the real issue
Yeah, it's pretty much hopeless
Get out on the next pre-earnings bounce
There's nothing left to do but sell everything
I'm still up 5 million yen right now though
Depends on your risk tolerance
If you can wait it out for another rally, just leave it be
Even if CoreWeave goes bankrupt, AI investment isn't going to stop
It's happening because the market's judging that fundraising will slow down overall now that they have to issue high-interest bonds to raise capital
Defensive stocks might even go up, if anything
Yeah, there were even some defensive names that rose during the last crash
Isn't that a 'gap' (window), not a 'door'? (in Japanese stock-chart jargon, a price gap is called a 窓, literally 'window')
I think it might turn into a Black Monday
Tomorrow the Nikkei's going to break below the support line it's been building since July
There's a real chance it keeps sliding over the next month or so and drops below 60,000
Even buying the dip tomorrow would be an awkward position
But it should climb back up again by year-end
Exactly
It's all downside
Just hold off a bit longer
Till around December
Should've cut my losses around -25%
I cut my losses at 2.5 million yen
Background and Key Points of This Discussion
At the heart of this discussion is the rise in bond yields at CoreWeave, the GPU-rental company underpinning the AI investment boom. Posters in the thread noted that the yield increase stemmed from bondholders dumping the debt after interest costs began outpacing profit growth, splitting opinion between those who saw it as “old news, nothing to be surprised about now” and those who argued “this time it’s qualitatively different, since profits aren’t keeping up with interest burdens.” Another point of contention was the differing positions of investors using NISA (Japan’s tax-free investment account): those already sitting on unrealized gains versus those who’d only started in September of this year and suddenly found themselves facing a downturn disagreed over whether to sell or hold. One forecast floated in the thread — that the Nikkei would break its support line and fall into the 60,000-yen range — should be treated with caution, as it is strictly an anonymous poster’s technical analysis, not a confirmed outlook.
*This article is compiled and summarized from the 5ch (Nandemo Jikkyo G) thread “Nikkei Average Stock Price — Four Digits Guaranteed by Tomorrow“.
