"Mrs Watanabe" Returns, Retail Investors Dominance in Japanese Stocks Reaches Post-Abenomics High

The Japanese retail investors once known for foreign exchange arbitrage, colloquially referred to as "Mrs. Watanabe," are shifting their funds from exchange rate differences to AI-related individual stocks. According to data from JPX, the parent company of the Tokyo Stock Exchange, the daily average stock turnover on the mainboard of the Tokyo Stock Exchange exceeded 10 trillion yen, approximately $63 billion, for the first three weeks of May. Oki Matsumoto, founder of one of Japan's largest online brokers, Monex, stated outright that the level of retail investor activity in the Japanese market is currently at its highest in history.

The rise in retail investor share is supported by data. Tokyo Stock Exchange data shows that the retail transaction share reached 25% in 2025, the peak since the bull market triggered by Abenomics. Jefferies' analysis suggests that the actual increase may be underestimated—Tokyo Stock Exchange's statistics do not include the trading volume of off-exchange proprietary trading platforms. After integrating alternative exchange data, the total trading volume of retail investors and alternative exchanges accounted for 39% of the entire market in April of this year.

There is also a structural change in the flow of funds. Oki Matsumoto pointed out that in the past, the largest trading scale of retail investors was concentrated on ETFs that track the broad market, but now, the trading volumes of AI-related individual stocks such as Furukawa Electric and Fujikura have surpassed the previous. "Retail investors are no longer just buying the broad market but are buying specific individual stocks, which is quite unusual," he said.

The expansion of retail investors is reshaping the characteristics of market volatility. Jeff Hutchins, Head of Japanese Equity Trading at Jefferies, described the market structure as "institutions set the direction, retail investors create volatility," and warned that during the just-concluded earnings season, any Japanese technology company with positive momentum, even if expectations are slightly lowered, will see its stock price severely punished. Stocks such as Nitto Boseki, Mitsui E&S, Ajinomoto, and Fujikura are all considered to be significantly influenced by the behavior of retail investor funds.

It is worth noting that despite the continuous rise in participation, retail investors are still net sellers at the Tokyo Stock Exchange level, with some families gradually reducing their long-held stocks by taking advantage of rising stock prices. The continuous net buying force in the Japanese market still mainly comes from foreign institutional investors and domestic corporations.