Goldman Sachs Warns of Breakup in Dominance of Mega-Tech Stocks, Market Concentration Turning Point Emerges

For over 15 years, global markets have been dominated by a handful of hyperscale technology companies. However, according to recent research reports, this era of concentrated market power may now be reaching a structural turning point, with a significant shift in the balance of power underway.

Analysts from institutions such as Goldman Sachs and Apollo warn that investors should prepare for a more diversified, earnings-driven 'Great Diversification' era, driven by rising AI capital expenditure pressures and changing macroeconomic conditions.

### Erosion of Tech Giants' Advantage

Peter Oppenheimer, Goldman Sachs' Chief Global Equity Strategist, notes that while the tech sector may not currently exhibit a traditional 'valuation bubble,' it could be entering an 'earnings bubble.' Since the rise of ChatGPT, tech giants have engaged in an aggressive capital spending race to maintain AI leadership. This massive expenditure is fundamentally altering the financial structure of tech stocks, steadily eroding their once-proud free cash flow.

Data shows that the cash flow yield advantage once held by these hyperscalers has significantly narrowed compared to other value markets, such as Europe. This has nearly eliminated the premium valuation tech stocks once enjoyed, pushing the market into a 'healthy normalization' process.

### Rise of Equal-Weighted Indices

The most visible evidence of the breakdown in monopolistic dominance is the broadening of market participation. Since 2009, the equal-weighted S&P 500 index has outperformed the market-cap-weighted index by over 7.3% for the first time. This reflects a shift in U.S. equities away from reliance on a few 'large-cap' stocks, with capital now flowing into undervalued traditional industries, Japan, Europe, and emerging markets.

Torsten Slok, Apollo's Chief Economist, further warns that the traditional 60/40 investment portfolio (60% stocks, 40% bonds) has become ineffective. He argues that with AI trading enthusiasm cooling and amid high inflation and government debt reaching 175% of GDP, the investment logic of the past 40 years is being fundamentally challenged.

### Outlook: Return to Fundamentals and Diversified Allocation

This market shift is not driven by sentiment alone but is grounded in solid earnings growth.

With higher interest rates expected to persist ('higher for longer'), earnings growth—rather than mere valuation expansion—has become the core driver of equity returns. The spillover effects of large-scale AI capital spending are now driving the revaluation of long-neglected sectors such as energy, defense, and critical infrastructure.

Goldman Sachs believes that as stock correlations decline and leadership rotates across sectors, balanced, cross-regional, and cross-industry asset allocation will be key to achieving real returns. Investors must shift from the extreme concentration of the past decade toward a more comprehensive asset allocation to adapt to structural changes in the investment landscape.