Global financial portfolios face mounting concentration risks as investors crowd into past market winners, according to investment managers surveyed by CNBC. Amid volatile market conditions that have continually shifted leadership between sectors, portfolio strategists emphasize that diversifying beyond mega-cap technology and U.S. equities is critical for managing contemporary risks.
Fading U.S. exceptionalism and the case for global diversification
Investors taking on excessive concentration risk in past market leaders are missing broader global opportunities, according to Chris Rush, investment manager at IBOSS. Speaking to CNBC, Rush pointed out that U.S. equities already comprise an outsized share of global portfolios. At the same time, U.S. exceptionalism has started receding from pre-2025 levels, while escalating debt burdens among the Magnificent Seven companies heighten the danger of continually chasing identical tech names.
To counteract these pressures, Rush’s team is broadening allocations into real estate investment trusts, which he noted “have been out of favor for years but now look increasingly attractive” from a valuation perspective. Additional portfolio wideners include U.K. equities alongside stocks in Asia and emerging markets. While investors have heavily targeted artificial intelligence winners in Korea and Taiwan, China has demonstrated strong performance during recent market pullbacks, keeping it well-positioned, according to Rush.
Pro Tip: Strategists recommend looking beyond localized tech leadership by rebalancing into undervalued sectors such as real estate investment trusts and international equities to mitigate concentration risk.
Managing specific volatility without playing the hero
The primary hurdle for market participants has not been overall volatility, but rather sector-specific swings where leadership shifts rapidly, according to Ben Kumar, head of strategy for wealth, investment and public policy at 7IM.
“Everything has worked at some points, nothing has worked at all points,” Kumar said, emphasizing that broad diversification across sectors and regions has helped immensely. He cautioned investors against attempting aggressive market timing, stating, “You don’t need to be a hero in this market — just let it work for you, and keep your exposures broad. Don’t die trying to be a hero.”
Navigating competing macro forces and policy binds
Seager-Scott told CNBC that markets risk becoming complacent regarding Middle Eastern events, persistent inflationary pressures, and structural shifts in the artificial intelligence trade.
In response, Forvis Mazars has trimmed equity risk overweights while rotating away from mega-cap technology names into ordinary U.S. stocks, transitioning from market-cap-weighted exposures to equal-weight exposures. Meanwhile, Charlie Ambler, co-chief investment officer and partner at Saltus, identified a critical policy bind as the primary portfolio risk. Central banks are struggling to control long-term rates just as the economy absorbs a capital-hungry and inflationary artificial intelligence infrastructure buildout, according to Ambler, leaving policymakers caught in an uncomfortable trade-off between inflation control and financial stability.
| Strategist | Firm | Primary Risk Identified | Portfolio Action |
|---|---|---|---|
| Chris Rush | IBOSS | Over-concentration in past U.S. winners | Add REITs, U.K., Asian, and emerging market stocks |
| Ben Seager-Scott | Forvis Mazars | Geopolitical conflict and market complacency | Rotate to equal-weight U.S. exposures |
| Charlie Ambler | Saltus | Central bank interest rate policy bind | Widen exposures across equities, fixed income, and alternatives |
AI capital spending and the durability debate
Beyond macroeconomic policy, market observers are monitoring the sustainability of technology investments. Steve Brice, global chief investment officer at Standard Chartered, told CNBC that the primary cyclical risk involves any disruption to the global artificial intelligence boom, while fiscal policy and inflation represent the top structural risks. Brice warned against a heavy barbell approach of buying growth while holding excessive cash, advocating instead for increased allocations to developed market financials, euro area industrials, bonds, and gold.
Echoing these concerns, Billy Leung, investment strategist at Global X ETFs, pointed to the sheer scale of financing committed to artificial intelligence infrastructure—reaching hundreds of billions of dollars—which has reignited debates over circular financing structures and weak free cash flow conversion. Leung noted that positioning data shows equity investors operating under an under-hedged posture with implied volatility drifting toward one-year lows, making artificial intelligence capital spending durability the most likely trigger for future market repositioning.
Did you know? Implied volatility across major market indices and exchange-traded funds has drifted near one-year lows, signaling broad-based bullishness among equity investors rather than defensive positioning, according to data cited by Global X ETFs.
Frequently Asked Questions
What is the biggest risk identified by investment managers for portfolios?
According to investment managers surveyed by CNBC, key risks include over-concentration in past market winners, a central bank policy bind regarding interest rates, geopolitical tensions, and uncertainties surrounding artificial intelligence capital expenditure durability.
How are strategists responding to market concentration risks?
Strategists from firms like IBOSS, Saltus, and 7IM are broadening their portfolios by diversifying into international equities, real estate investment trusts, fixed income, and alternative asset classes rather than chasing mega-cap technology stocks.
Why are analysts concerned about artificial intelligence infrastructure spending?
Analysts highlight that the hundreds of billions of dollars committed to artificial intelligence capex have raised valid questions regarding weak free cash flow conversion and circular financing structures across parts of the technology ecosystem.
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