[Deep Dive] Prolonged Weak Yen and Rebound of Large Japanese Export Stocks: Macroeconomic and Market Impacts

Prolonged Weak Yen and Its Macroeconomic Context

As of the first half of 2026, the depreciation of the Japanese yen has been prolonged beyond initial expectations, acting as a critical variable in global foreign exchange markets and asset allocation. Despite the Bank of Japan's (BOJ) gradual normalization of interest rates, the enduring high-interest-rate environment maintained by the U.S. Federal Reserve and the unyielding interest rate differential between the two nations remain the primary drivers of the yen's sustained weakness.

The U.S.-Japan Interest Rate Differential and Limits of Currency Intervention

The policy interest rate spread between the United States and Japan currently remains at an elevated level. Although sporadic market interventions and verbal warnings from the Japanese Ministry of Finance provide temporary volatility in the FX market, a trend reversal toward a stronger yen proves difficult without fundamental shifts. As of June 2026, the real effective exchange rate indicator hovers near its lowest point in three decades, directly inducing changes in the real economy through import and export unit prices.

The Policy Dilemma of the Bank of Japan (BOJ)

The Bank of Japan recognizes the necessity of raising interest rates to counter inflationary pressures and the prolonged weak yen; however, it is tempering the pace of monetary policy normalization due to concerns that premature tightening could trigger an economic downturn. While the central bank is contemplating a gradual reduction in government bond purchases and an increase in short-term rates in its policy meetings for the second half of 2026, the market assesses that these measures are insufficient to drive a sharp rebound in the yen's value. Unless the negative growth in real wages is resolved, aggressive tightening policies could act as a boomerang, severely contracting domestic consumption.

Structural Profit Leverage in Large Export Stocks

A weak yen environment traditionally fosters favorable conditions for Japan's export-driven enterprises. Specifically in 2026, distinct margin improvements are being realized in the automotive, machinery, and semiconductor materials, components, and equipment sectors through foreign exchange gains.

Upward Revisions in Operating Profits for Auto and Machinery Sectors

Major automakers and precision machinery companies have reported double-digit year-over-year operating profit growth, supported by currency effects. For large corporations with overseas revenue dependencies exceeding 70%, every 1-yen depreciation against the dollar generates tens of billions of yen in additional operating income. This translates into expanded free cash flow (FCF), which is actively utilized to fund shareholder return policies such as share buybacks and increased dividends.

Semiconductor Value Chain and Strengthened Global Competitiveness

Beyond mere price competitiveness, the positioning of Japanese materials and equipment companies is strengthening amid the restructuring of the global semiconductor supply chain. Coupled with surging demand for high-performance computing (HPC) and AI, the exchange rate effect secures these companies' capacity for reinvestment in research and development (R&D). Consequently, companies are moving beyond defending market share through lower export prices, actively pursuing fundamental structural improvements via product mix enhancement.

Global Capital Inflow Trends in the Japanese Stock Market

The combination of improving corporate earnings and shareholder-friendly policies is driving global investors to increase their weighting of Japanese equities within their portfolios.

Relative Strength of Nikkei 225 and TOPIX Indices

Recently, the Nikkei 225 and TOPIX indices have demonstrated robust downside rigidity compared to major Asian equity markets. Aligned with corporate value enhancement initiatives led by the Tokyo Stock Exchange (TSE)—such as demanding improvements from companies trading below a price-to-book ratio of 1—foreign investors have consistently net-bought Japanese stocks across both passive and active funds. Data indicates that during the second quarter of 2026, foreign investors executed concentrated capital allocations primarily targeting large-cap and value stocks.

Implications for the South Korean Stock Market

The relative strength of the Japanese stock market poses a potential supply-demand pressure on South Korean equities during the rebalancing of global passive funds within the Asia region. Particularly in sectors with high export competition against Japanese firms—such as automotive, steel, and specific machinery industries—close monitoring is required to determine whether the aggressive pricing strategies of Japanese companies, backed by the weak yen, are constraining the margin defense capabilities of domestic enterprises.