The prolonged period of high concentration in U.S. stocks, lasting over 15 years, is beginning to unravel. In a recent report, Goldman Sachs' Chief Global Equity Strategist Peter Oppenheimer stated that global equity markets are undergoing a healthy normalization process. Market returns are spreading across both geographic regions and industry sectors, making the value of diversification significantly more pronounced. Since the start of 2025, this trend of "broad diversification" has notably accelerated. The U.S. stock market has been the weakest among major regions, while Japan, Asia-Pacific, and emerging markets have recorded the strongest gains in local currency terms.

Meanwhile, massive capital expenditures by hyperscalers continue to erode their free cash flow yields, driving valuation adjustments in the tech sector. The spillover effects, however, are boosting the growth prospects and valuations of traditional industries, such as industrials. In his global strategy report titled "Momentum, Rotation, and Value in Growth," Oppenheimer emphasized that the driving force behind this market rotation is earnings fundamentals, not valuation expansion or lower interest rates. He believes that the extreme concentration in market capitalization and earnings, which has persisted for over a decade, is now facing a structural shift. The opportunity for investors to generate returns from truly diversified portfolios is increasing.

Tech Sector Valuations Under Pressure, Free Cash Flow Advantage Narrows

In the decade following the financial crisis, the tech sector enjoyed a sustained rise in profit margins and return on equity (ROE) due to its asset-light model, a surge in demand for cloud computing and software, and valuation premiums in a zero-interest-rate environment, making it a core allocation for global capital. However, the emergence of ChatGPT ignited a capital expenditure race among mega-cap tech companies. Oppenheimer pointed out that this capital expenditure super-cycle is fundamentally altering the financial characteristics of the tech sector. The massive investments are continuously eroding free cash flow, forcing these companies to turn to debt and equity markets for financing. Measured by free cash flow yield, the advantage of the U.S. stock market, dominated by mega-cap tech, over value-oriented markets like Europe has significantly narrowed. This provides fundamental support for the recent relative performance rotation. Additionally, higher government debt, persistent inflationary pressures, and increased bond supply are collectively raising the cost of capital, making profit growth the primary driver of stock market returns.

Earnings-Driven Rotation Triggers a Revaluation of Traditional Industries

Notably, this market broadening is not driven by a valuation bubble or loose monetary policy but is built on solid earnings growth. Oppenheimer stressed that not only are earnings themselves strong, but the direction of earnings estimate revisions is also consistently upward, providing a double confirmation of the fundamental support for the stock market. The massive capital expenditures from mega-cap tech companies and chip firms, combined with increased government fiscal spending on energy security, critical infrastructure, and national defense, have together created a capital expenditure super-cycle. The spillover effects of this cycle are reactivating long-overlooked traditional industries. The growth prospects and valuations of sectors like industrials are receiving a clear boost. At the country level, ROE across regions remains high overall, while stock correlations are declining. As the market's leading sectors continue to rotate, opportunities for alpha generation are increasing. Oppenheimer believes that although the overall P/E ratio of the U.S. stock market has declined due to the tech sector's drag, from an ROE perspective, the U.S. market remains the most attractive in the world.

Concentration Turning Point Confirmed, Diversification Value Returns

Goldman Sachs argues that the decline in stock correlations and the rapid unraveling of recent momentum strategies are accelerating the shift in market leadership, creating a more favorable environment for investors to select value within the growth space. Oppenheimer's core judgment is that after more than a decade of extreme concentration in both market capitalization and earnings, global equity markets are undergoing a healthy normalization, and diversification is once again delivering real returns. He expects this trend to continue evolving. For investors, this means the strategy of betting solely on U.S. mega-cap tech stocks is losing its appeal, while the logic for a balanced allocation across regions and sectors is re-establishing itself.