Bank of Japan (BOJ) Impact on Nikkei 225: SMFG and Key Stocks — Backtest Data

Today's Market Focus: Bank of Japan (BOJ)

"日銀レートチェック再び、連休前に円安けん制 投機筋｢不意突かれた｣" — Bank of Japan (BOJ) is dominating Japanese financial headlines today. This article analyzes how this macro development specifically impacts Nikkei 225 stocks, using Kabu Prediction's 10-year backtest data (2016–2026) to identify which stocks show the strongest statistical response.

Today's Bank of Japan (BOJ) Headlines

• 日銀レートチェック再び、連休前に円安けん制 投機筋｢不意突かれた｣
• 植田日銀のかじ取り、ベッセント長官と高市首相の間で一段と困難に
• 【速報解説】日銀利上げでも円安進行、ドル円は再び160円に戻る？9月日銀会合後の相場見通し＆今後の注目点｜佐々木融 2026年9月18日
• 日銀の利上げでも円安…深夜に1円以上円高 介入準備のレートチェックあったか
• 日銀が「レートチェック」を実施 円安けん制か | NHKニュース | 日本銀行（日銀）、株価・為替

Bank of Japan (BOJ) and the Nikkei 225: The Quantitative Relationship

Macro variables like Bank of Japan (BOJ) are among the most powerful drivers of Nikkei 225 stock prices. Kabu Prediction's SHAP analysis shows that macro drivers explain 30–60% of price movements for many Nikkei 225 stocks. Understanding this relationship quantitatively — rather than relying on intuition — is the key to rule-based investing.

Stock Spotlight 1: SMFG (8316)

According to Kabu Prediction's 10-year backtest: SMFG (8316) has a 1-week win rate of 73.7%, edge of +14.0%, and Sharpe ratio of 0.0. The dominant driver is "technical", with "momentum_negative_20d" as the best-performing rule (133 signals). Full analysis: https://kabu.microforge.works/stocks/8316

Stock Spotlight 2: Mizuho FG (8411)

Mizuho FG (8411): 1-week win rate 58.0%, edge +18.1%, Sharpe 0.0. Best rule: "BB_upper_touch" (112 signals). https://kabu.microforge.works/stocks/8411

Stock Spotlight 3: MUFG (8306)

MUFG (8306): 1-week win rate 73.2%, edge +16.0%. https://kabu.microforge.works/stocks/8306

What Is Kabu Prediction?

Kabu Prediction (https://kabu.microforge.works) is a free platform that analyzes all Nikkei 225 stocks using 45 AI-discovered statistical rules. Unlike black-box AI models, every rule's condition, win rate, edge, and backtest data is fully disclosed. No registration required.

How to Read Win Rate and Edge

"Win rate" = the percentage of times the rule correctly predicted the direction of price movement. "Edge" = excess return above what you'd get by always holding (baseline). A win rate above 50% combined with a positive edge indicates a statistically advantaged rule.

The 4-Horizon Framework

Kabu Prediction analyzes each stock across four time horizons: 3 trading days, 1 week, 1 month, and 3 months. For macro-driven topics like Bank of Japan (BOJ), the 1-month and 3-month horizons tend to show higher edge as the macro effect takes time to fully materialize in earnings and valuations.

Backtest Methodology

All backtests include 0.1% commission, 0.1% slippage, 20.315% capital gains tax, lot-size constraints (100-share units), and no overlapping positions in the same stock. These realistic conditions prevent overestimation of returns.

Summary

Today's trending topic "Bank of Japan (BOJ)" has quantifiable implications for Nikkei 225 stocks. SMFG (73.7% win rate, +14.0% edge) and Mizuho FG (58.0%) show strong statistical performance in relevant rule categories. Explore all data free at https://kabu.microforge.works

Disclaimer

This article presents statistical analysis results from Kabu Prediction and does not constitute investment advice or a recommendation to buy or sell any financial instrument. All win rates and edge figures are historical backtest results and do not guarantee future performance. All investment decisions are made at your own risk.