Japan Equity Strategy: Stick with AI Momentum, Balance with Value to Hedge Rate Hikes

Overview

This research report focuses on style allocation strategies for the Japanese equity market in June 2026. The core conclusion is that against the backdrop of sustained strong global demand for AI semiconductors, the structural rally in Japanese stocks led by AI-related sectors is likely to continue, but the momentum factor has shown clear signs of overheating. Considering the rising expectation that the Bank of Japan (BOJ) may adopt a hawkish stance on rate hikes in June, and the pressure for correction in the extreme divergence between winning and losing sectors, the report suggests maintaining a selective overweight on the AI momentum factor in the medium term, while hedging and rebalancing in the short term by increasing allocation to targets with both value and momentum characteristics to cope with potential macroeconomic volatility and style switching risks.

Core views

AI semiconductors remain the core driver of Japanese stocks, but signs of overheating in the momentum factor are evident. In May, the Nikkei 225 Index approached 68,000 points, mainly boosted by weighted stocks related to semiconductors and AI infrastructure. Not only core semiconductor and equipment stocks rose, but the AI infrastructure chain also benefited significantly. Strong earnings expectations have led fundamental investors to buy on dips during momentum factor pullbacks, limiting downside space. However, from a quantitative perspective, the valuation premium of the momentum factor continues to widen, its portfolio's risk exposure has reached a record bias toward high-beta and large-cap stocks, and quality factor exposure has declined, showing clear signs of crowding and overheating. Nevertheless, given the solid fundamental support for the AI boom, the report believes it is unwise to exit completely at this stage, and maintaining a 'selective overweight' is more appropriate. The macroeconomic cycle remains in the expansion phase, but marginal slowdowns and policy risks warrant caution. JPMorgan's proprietary Japan Quantitative Macro Indicator (QMI) improved month-on-month in May, continuing to reside in the 'expansion' quadrant. The upward cycle in global capital expenditure and AI demand offset the negative impact of the Strait of Hormuz situation on parts of the non-manufacturing sector, with manufacturing showing resilience beyond expectations. However, recent improvements partly stem from one-off benefits such as memory chips, making it statistically difficult to sustain the current acceleration pace over the long term. A greater risk lies in monetary policy: although the market has priced in a June rate hike, it has underpriced the possibility that the BOJ may take more hawkish measures than expected due to inflation. If hawkish rate hikes materialize, they could impact high-valuation, high-beta pure momentum strategies and prompt funds to reassess lagging value stocks. Style divergence is extreme, making the value + momentum combination the preferred short-term hedge. Performance in May showed polarized styles: momentum, size (large-cap), and high-beta factors significantly outperformed; while low volatility, quality, and ROE, which are defensive or earnings-quality factors, performed worst. This extreme divergence increases the probability of mean reversion. The report points out that within the group of value stocks, there exists a batch of targets that also possess moderate momentum characteristics. When the market rotates from pure AI momentum sectors due to rate hike concerns or profit-taking, this 'value + momentum' intersection is expected to become a safe haven for funds. Therefore, the tactical recommendation for June is: while sticking to the AI main line without wavering, use this intersection for defensive allocation to smooth portfolio volatility and hedge against macro tail risks.

Analysis framework

The report adopts a four-step analysis framework of 'Macro Cycle Positioning → Factor Performance Attribution → Microstructure Diagnosis → Tactical Allocation Mapping'. First, it uses the self-developed Japan QMI (Quantitative Macro Indicator) to determine the economic cycle stage (Recovery/Expansion/Slowdown/Contraction), thereby establishing the baseline direction for style allocation; the current QMI points to an expansion phase, which theoretically favors cyclical, value, and momentum factors. Second, by tracking the monthly long-short returns, Sharpe ratios, and industry attribution of various style factors (such as momentum, value, low volatility, etc.), it identifies the leading and lagging factors of the period and their drivers. The third step is a key innovation: deeply analyzing the 'spread' indicators of factors, including valuation spread (P/B Spread) and risk spread (Beta Spread), and comparing them with the past 10-year averages to quantify factor crowding, cost-effectiveness, and potential reversal risks. For example, when the Beta spread of the momentum factor hits a historical high, it is regarded as an overheating warning. Finally, combining the above quantitative signals with qualitative macro judgments (such as central bank policy expectations), it derives specific style overlay or hedging strategies (such as Value-Momentum intersection screening).

Methodology notes

• Cycle and Prosperity FrameworkProsperity Inflection Point Analysis

  QMI (Quantitative Macro Indicator) Four-Quadrant Cycle Positioning

  The report uses the self-developed QMI indicator to divide the macroeconomy into four quadrants: recovery, expansion, slowdown, and contraction. Different quadrants correspond to different dominant styles: for example, in the 'expansion' quadrant, it is usually advisable to overweight cyclical, value, large-cap, and momentum factors. In this report, the QMI is in the expansion zone, setting an offensive allocation tone, but extra caution against overheating is needed due to the prolonged duration.

• Quantitative/Factor/Portfolio TheoryStyle factor analysis

  Factor Spread Diagnosis of Crowding

  The report not only looks at factor rises and falls but also focuses on monitoring the deviation of the 'spread' between factor long and short portfolios in terms of valuation (P/B) and risk (Beta) relative to the 10-year average. When the Beta spread of a factor (such as momentum) reaches a record high, it means the long portfolio is extremely biased toward high-risk assets, which is a key quantitative signal for judging factor trading crowding and predicting potential reversal risks.

• Quantitative/Factor/Portfolio TheoryMulti-factor model

  Factor Interaction and Intersection Stock Selection (Value-Momentum Overlap)

  The report does not view single factors in isolation but focuses on the interaction effects between factors. By selecting stocks that are simultaneously in the high percentile of the 'value' factor and the positive loading range of the 'momentum' factor, a composite strategy is constructed. This method utilizes the low correlation between factors or their complementarity in specific periods, aiming to retain upside elasticity while reducing the drawdown risk of single momentum strategies during policy shifts.

Key data

• Nikkei 225 Index LevelApproaching 68,000 pointsLevel in early June, hitting a phased new high driven by AI semiconductor weighted stocks
• Momentum Factor May Return+6.4%The best-performing style factor in the broader market in May, mainly contributed by the Information Technology and Communication Services sectors
• Low Volatility Factor May Return-11.1%The worst-performing style factor in the broader market in May, with defensive assets remaining under pressure against the backdrop of inflation and rising interest rates
• Momentum Factor Beta Spread2.18Significantly higher than the 10-year average, showing that the momentum portfolio's risk exposure is record-biased toward high-beta stocks, with clear overheating signals
• Japan QMI StatusExpansionImproved month-on-month in May; manufacturing showed resilience supported by AI demand, but the improvement speed includes one-off factors

Impact & implications

For investors in the Japanese stock market, the current environment means that 'going with the flow' and 'being prepared for danger in times of peace' must proceed in parallel. On one hand, the earnings realization capability of the AI semiconductor industry chain remains the most certain source of alpha in the market, and exiting too early may miss the main upward wave; on the other hand, extreme style divergence and the potential for a hawkish central bank constitute significant tail risks. This means that the cost-effectiveness of purely chasing hot AI targets is declining, and the precision of portfolio management becomes crucial. By introducing 'value + momentum' composite factor exposure, investors can optimize risk-adjusted returns without significantly reducing positions, leaving a cushion for potential macroeconomic disturbances. In addition, the extreme undervaluation of low volatility and value stocks also implies that once rate hike expectations are fully digested or economic data weakens, these sectors may experience a violent catch-up repair.

Risks

• The Bank of Japan adopts more hawkish rate hike measures than expected by the market, leading to severe adjustments in high-valuation growth stocks
• Cyclical slowdown in AI semiconductor demand or fading of one-off benefits leads to the collapse of fundamental support for the momentum factor
• Rapid mean reversion occurs in the extreme divergence between winning and losing market sectors, triggering significant drawdowns in momentum strategies
• Escalation of geopolitical tensions in the Middle East (such as issues in the Strait of Hormuz) pushes up commodity prices and drags down the non-manufacturing sector

What to watch

• Wording of the Bank of Japan's June monetary policy meeting and subsequent guidance on the rate hike path
• Marginal changes in the momentum factor's valuation spread and Beta spread to judge whether crowding has peaked
• Capital inflows and relative performance in the overlapping area of value and momentum factors
• Global AI semiconductor capital expenditure data and the sustainability of special demands such as memory chips
• Signals indicating whether the Japan QMI indicator is switching from the expansion quadrant to the slowdown quadrant