For years, passive investing through exchange-traded funds (ETFs) has been hailed as one of the simplest and most effective ways to build wealth. The strategy of buying index-based ETFs like the Vanguard S&P 500 ETF (VOO) and holding them long-term has attracted millions of investors who prefer steady growth over active trading. However, a growing number of financial professionals and investors now believe that this once-dominant approach may be losing its luster.

According to Gavin Filmore, Chief Revenue Officer at Tidal Financial Group, many clients are no longer satisfied with the traditional “buy the index and chill” method. In a recent interview with CNBC’s ETF Edge, Filmore explained that investors are beginning to recognize the limitations of simply tracking major indexes such as the S&P 500.

“I think investors are looking beyond what I like to call the ‘VOO and chill’ approach,” Filmore said. “It’s still a solid strategy, but people want more diversification. They’re realizing that buying one ETF that tracks a large market index doesn’t necessarily mean they’re properly diversified.”

VOO, which mirrors the performance of the S&P 500, has risen nearly 16% this year, demonstrating continued strength in U.S. large-cap equities. Yet Filmore suggests that behind this headline performance lies a concentration risk that could leave investors vulnerable.

Growing Concern Over Market Imbalance

Todd Sohn, Senior ETF and Technical Strategist at Strategas Securities, shares this concern. He describes the current state of the S&P 500 as “imbalanced,” noting that a small group of large-cap technology companies now dominates the index to an unprecedented degree.

“Imbalance is the perfect word,” Sohn said. “Technology now makes up more than 35% of the S&P 500 — the highest level in history.”

This heavy concentration in tech stocks means that the performance of just a few companies can significantly influence the index. As a result, investors who think they’re diversified by owning an S&P 500 ETF may actually be taking on more sector-specific risk than they realize.

FactSet data shows that defensive sectors such as consumer staples, health care, energy, and utilities now represent just 19% of the index — the lowest share ever recorded. This shrinking representation of traditional, stable industries underscores the growing imbalance that concerns analysts like Sohn.

A Shift Toward Small-Cap Opportunities

As confidence in the large-cap space begins to waver, investors are exploring other opportunities. Sohn notes a rising interest in small-cap stocks, which have recently shown signs of strong momentum.

The Russell 2000 Index, which tracks small-cap companies, hit an all-time high this week and logged its best performance since August. Over the past six months, it has surged more than 28%, outpacing the S&P 500’s gains. Earlier this month, the index surpassed 2,500 points for the first time in its history — a clear sign that investors are rotating toward smaller, more diverse holdings.

Sohn believes this trend may reflect a broader shift in investor behavior. “I think we’re starting to see a broadening of market participation,” he said. “Investors who are already heavily exposed to technology and artificial intelligence sectors are now seeking other routes to capture growth while spreading their risk.”

Balancing Growth with Diversification

The renewed enthusiasm for small-cap stocks suggests that investors are becoming more selective and tactical in their approach. Rather than relying solely on the passive growth of major indexes, they’re looking for areas of the market that may have been overlooked or undervalued.

Filmore notes that diversification today requires more than just holding a few ETFs. “People used to think that buying one or two index funds meant they were diversified,” he said. “But now investors are realizing that true diversification might involve multiple asset classes, regions, and investment styles.”

This shift doesn’t necessarily mean the end of passive investing, but it highlights a growing awareness of its limitations. With large-cap technology firms dominating the market and driving much of the index’s performance, some investors fear that a downturn in this sector could have an outsized impact on their portfolios.

The “Magnificent 7” and Market Expectations

Next week, market attention will likely return to the big names that continue to shape the narrative on Wall Street. Five of the so-called “Magnificent 7” — Meta Platforms, Alphabet, Microsoft, Apple, and Amazon — are set to release their latest earnings reports.

These companies have been major contributors to the S&P 500’s gains in recent years, fueled by enthusiasm around artificial intelligence, cloud computing, and digital advertising. However, their dominance also underscores the very imbalance that has prompted investors to rethink their strategies.

If the upcoming earnings results are strong, the S&P 500 could continue its upward trajectory. But any signs of weakness among these tech giants might accelerate the ongoing shift toward smaller, more diversified holdings.

Looking Ahead

The debate between passive and active investing has long been a defining theme in modern finance. For the past decade, passive strategies have reigned supreme, offering simplicity and low costs. Yet as markets evolve, investors are learning that even passive approaches require active thought and vigilance.

In an environment where a handful of tech stocks can make or break an index, many are beginning to seek balance — blending the efficiency of ETFs with the adaptability of targeted investments.

As Filmore puts it, “The beauty of ETFs is their flexibility. Investors can still use them as a core part of their portfolio but need to be more thoughtful about how they’re allocated.”

In short, while passive investing is far from dead, it’s entering a new phase — one that demands greater awareness of market concentration and a more intentional pursuit of true diversification.