Japanese retail investors, once globally renowned as "Mrs. Watanabe" for their enthusiasm in currency carry trades, are now shifting their focus from exchange rate differentials to the capital markets of the AI era. Their participation has surged to its highest level in decades, significantly amplifying market volatility.

According to data from JPX, the parent company of the Tokyo Stock Exchange (TSE), the average daily trading value on the TSE's main board exceeded ¥10 trillion (approximately $63 billion) for the first time in the first three weeks of May. Foreign funds and domestic investors are competing to bet on Japanese tech companies, viewing them as beneficiaries akin to "shovel sellers" in the AI wave and semiconductor competition, collectively driving stock prices to record highs.

This surge in trading volume coincides with a rapid expansion in over-the-counter (OTC) trading. Securities firms note that the influence of retail investors on market trends has reached an unprecedented level. Oki Matsumoto, founder of Monex, one of Japan's largest online brokerages, stated that the "AI boom" has swept through Japan's retail investor community, bringing a large number of investors into the market. Retail activity in the Japanese market is currently at an all-time high.

Analysts warn that the Japanese stock market, already one of the world's most momentum-driven markets, is seeing its volatility further amplified by the continued expansion of retail participation. Particularly during the recent earnings season, stocks faced severe market punishment even for minor misses against expectations.

**Retail Participation Hits Highest Level Since Abenomics**

TSE data shows that the proportion of retail trading on the exchange has steadily increased for over a quarter-century, reaching 25% in 2025, its peak since the bull market triggered by Abenomics.

However, according to analysis by Jefferies, the actual increase in retail investment may be underestimated. TSE data does not include the trading volume contributed by the burgeoning proprietary trading systems—OTC platforms—which are attracting a growing share of investor funds. After incorporating data from alternative exchanges, Jefferies analysts estimate that combined retail and alternative exchange trading accounted for 39% of the total market in April.

Japan's OTC proprietary trading platforms are currently dominated by Japannext and Japan Alternative Market (JAX), both of which have partnerships with online brokerages like Rakuten Securities, SBI Securities, and Monex. According to Takeya Kamei, CEO of JAX, about half of the exchange's trading volume comes from retail investors, with the remainder primarily from high-frequency market makers providing liquidity. Notably, the TSE's statistical scope also does not fully cover some margin trading by retail investors, with related data categorized under "brokers."

Analysts caution that there is some risk of double-counting in the above data, but the overall trend indicates that the activity level of Japanese retail investors has recovered to a height not seen since the asset bubble era of the 1980s.

**Retail Investors Fuel Intraday Swings, Individual Stock Moves Become More Extreme**

Oki Matsumoto describes the market structure as "the big picture set by institutions, volatility created by retail"—large institutional investors still dominate the overall market direction, but intraday volatility and price elasticity increasingly stem from the flow of retail funds.

Jeff Hutchins, Head of Japan Equity Trading at Jefferies, said: "The rise in Japanese retail trading volume is a significant shift. This market was previously dominated by international institutions. Now, there are new guests at the party, and we've seen the impact this earnings season." He added:

"Any Japanese company with positive momentum, especially in tech and AI, that slightly lowers expectations gets hit hard."

In this context, stocks such as Nitto Boseki, Mitsui E&S, Seikoh Giken, Ajinomoto, Furukawa Electric, and Fujikura are all believed to be noticeably influenced by the behavior of retail funds.

Oki Matsumoto pointed out that while ETFs tracking major indices previously attracted the largest trading volume from retail investors, the trading value of AI-related individual stocks like Furukawa Electric and Fujikura has now surpassed that. "Retail investors are no longer just buying the index; they are buying specific stocks. That's quite unusual," he said.

**Policy Tailwinds, But Retail Remains Net Sellers Overall**

The expansion of retail trading aligns with the Japanese government's policy intentions. Authorities are actively encouraging residents to shift savings from bank accounts into higher-yielding investments to address pension pressures amid an aging population, a move also in sync with the trend of rising domestic interest rates.

At the market infrastructure level, OTC proprietary trading platforms have developed rapidly in Japan. A decade ago, alternative exchanges accounted for only single-digit percentages of total market volume. Since then, regulators have explicitly supported the development of these platforms to introduce market competition. Industry insiders say this has positively impacted trading costs for retail investors.

However, a notable structural phenomenon is that despite the continuous increase in retail participation, at the TSE level, the overall flow of retail funds remains net selling. This indicates that some households are taking advantage of rising stock prices to gradually reduce their holdings of long-held stocks. Traditionally, the forces of sustained net buying in the Japanese market have primarily come from foreign institutional investors and domestic corporations.