Japanese Olympic Champion Jun Mizutani Invests for 8 Years with No Profit, Dreams of Earning 1 Yen
Japanese table tennis Olympic champion Jun Mizutani has been investing since 2018, suffering losses for 8 consecutive years, with his biggest dream being to earn an additional 1 yen in annual profit. During the interview, his account was forcibly suspended from trading due to insufficient margin.
During the 2024 Paris Olympics, his account required additional margin due to a market crash, and after entering the wrong password three times, it was locked. The unlocking letter could only be sent to Japan, and after his positions were forcibly liquidated by the brokerage, the market quickly rebounded.
In the early stages, Mizutani adopted a long-term holding strategy, buying 10 stocks and not touching them for 4 years. While the Nikkei index rose, his holdings continued to decline; one stock in his tax-free account had previously increased tenfold but is now down 90%.
Later, he shifted to high-leverage trading, borrowing money to increase his positions. After buying 14,000 shares of Kioxia, he sold them after a 3% drop, only to see them hit the daily limit up afterward. He panicked sold 30,000 shares of SoftBank Group after a drop, which rebounded the next day, realizing profits of 10%-20% on urgent sales, while holding losses until they reached 30%-40%.
In the summer of 2025, his annual profit once approached 100 million yen, but in an attempt to recover past losses all at once, he increased his bets, ultimately giving back all profits. He still dreams of earning 10 billion yen through investments.
Source: Public Information
ABAB AI Insight
Jun Mizutani's investment behavior exhibits typical psychological biases of "loss aversion + disposition effect": locking in profits at 10%-20% but holding losses until 30%-40%, reflecting the core prediction of behavioral finance's "Prospect Theory"—the pain of loss is 2-2.5 times greater than the pleasure of gain.
A similar case can be compared to the 2021 Archegos collapse: Bill Hwang also faced forced liquidation of hundreds of billions of dollars due to "selling profits quickly and holding losses," with the difference being that Mizutani used personal funds while Hwang used leveraged funds, but the psychological mechanisms are the same.
On the capital path, Mizutani shifted from "long-term holding" to "high-leverage speculation," reflecting a typical reaction of retail investors after "long-term ineffectiveness": instead of optimizing stock selection or risk control, they increase their bets, attempting to use leverage to compensate for inadequate stock-picking ability, ultimately falling into a "loss → increase leverage → greater loss" death spiral.
Essentially, this represents a transfer of pricing power: retail investors devolve from "value discoverers" to "liquidity providers," with the underlying mechanisms being a combination of information asymmetry and psychological biases, leading to "buy high, sell low" becoming a systemic behavior rather than an individual mistake.
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