Picking an Index Just to Avoid Big IPOs Isn’t Likely to Boost Returns

Understanding the Indexing Dilemma: Why Avoiding IPOs Isn’t the Alpha You’re Looking For

In the evolving landscape of modern finance, the rise of passive investing has fundamentally changed how individual and institutional investors interact with the stock market. For decades, the mantra has been simple: buy the index, lower your costs, and capture the broad market’s returns. However, as massive unicorns—private companies valued at over $1 billion—continue to debut on public exchanges with astronomical valuations, a new strategy has emerged among skeptical investors. Some are now attempting to select specific indices specifically to avoid the perceived volatility and overvaluation associated with large Initial Public Offerings (IPOs). While this might seem like a prudent risk-management technique on the surface, a deeper dive into market mechanics, index construction rules, and historical performance suggests that picking an index just to avoid big IPOs is unlikely to boost long-term returns.

The Psychological Hurdle of the ‘Hype Cycle’

To understand why investors want to avoid IPOs, one must first understand the psychological fatigue caused by the modern ‘hype cycle.’ When a company like Uber, Airbnb, or Snowflake goes public, it is often preceded by years of private market speculation and a media frenzy. By the time these companies reach the public markets, they are frequently valued at multiples that seem disconnected from their current earnings. Investors often fear that these companies are ‘priced for perfection,’ meaning any slight deviation from their growth trajectory could lead to a massive sell-off.

This fear isn’t entirely unfounded. Historically, many high-profile IPOs have underperformed the broader market in their first year of trading. This phenomenon has led some to believe that by choosing an index with stricter inclusion criteria—such as the S&P 500, which requires a history of profitability—they can ‘filter out’ the junk and keep only the proven winners. However, this strategy ignores the fundamental way that market-cap-weighted indices actually function and the protection already built into their methodology.

Index Methodology: The Built-In Filter

The most common misconception among those trying to avoid IPOs is that these new companies immediately flood every index. In reality, index providers like S&P Dow Jones Indices, FTSE Russell, and Nasdaq have rigorous, transparent rules regarding when and how a company can be added. For instance, the S&P 500 is not just a list of the 500 largest companies; it is a curated index managed by a committee. To be eligible for the S&P 500, a company must be a U.S. company, have a specific market cap, and, most importantly, show a sum of the most recent four consecutive quarters of positive earnings, as well as being positive in the most recent quarter.

This means that many of the most ‘dangerous’ or ‘hyped’ IPOs—those burning through cash to fuel growth—are ineligible for the S&P 500 for years. By the time a company like Amazon or Tesla was added to the S&P 500, they were already established giants. Therefore, switching from one broad-market index to another to avoid IPOs is often a solution in search of a problem. The ‘filtering’ that investors desire is often already happening behind the scenes through the index’s own eligibility requirements.

The Mathematical Insignificance of Single IPOs

Another reason why avoiding indices with IPO exposure rarely boosts returns is the sheer scale of modern benchmarks. In a market-cap-weighted index, the influence of any single company is proportional to its size relative to the total market. Even a massive IPO with a $50 billion valuation is a small fraction of a total market index like the CRSP US Total Market Index or the Russell 3000, which track thousands of companies with a combined valuation in the trillions.

When a new company is added to an index, its initial weighting is usually small enough that even a 20% or 30% drop in its share price has a negligible impact on the index’s total return. For an investor to see a meaningful boost in returns by avoiding an IPO, that IPO would have to be large enough to dominate the index and then perform spectacularly poorly, all while the rest of the index remains stable. Statistically, the diversification benefit of the other 499 or 2,999 stocks far outweighs the drag caused by a single underperforming newcomer.

The Risk of Missing the ‘Outliers’

Perhaps the greatest risk in choosing an index specifically to avoid IPOs is the opportunity cost. The power of the stock market is driven by a small number of ‘outliers’—companies that generate massive, multi-bagger returns over decades. Many of these companies, particularly in the technology and biotech sectors, are high-growth IPOs that may look expensive or volatile in their early public days.

If an investor chooses an index that is too restrictive in an attempt to avoid the ‘bad’ IPOs, they inadvertently risk missing out on the ‘great’ ones during their fastest growth phases. Missing out on just a handful of the top-performing stocks can lead to significant underperformance relative to the total market. This is the classic dilemma of active management versus passive indexing: by trying to avoid the losers, you often accidentally exclude the winners that drive the majority of the market’s long-term gains.

Market Timing and the Inclusion Effect

There is also the ‘inclusion effect’ to consider. Historically, when a large company is announced as a new addition to a major index, institutional demand often spikes as index-tracking funds are forced to buy the shares. This can lead to a short-term price increase. Conversely, some argue that by the time an IPO is added to an index, the ‘easy money’ has already been made by private equity and early public investors. While there is some truth to the idea that the ‘pop’ happens early, the long-term compounding of a successful business happens over decades, not days.

By selecting an index based on its IPO inclusion rules, an investor is essentially trying to time the market’s entry into a specific stock. Market timing is notoriously difficult, and doing so through the proxy of index selection adds a layer of complexity that rarely pays off. The costs associated with switching funds—such as capital gains taxes in taxable accounts and potential bid-ask spread costs—often outweigh any marginal gain from avoiding a specific IPO.

The Better Path: Broad Exposure and Low Costs

Instead of worrying about which index contains the fewest IPOs, investors are generally better served by focusing on the factors they can control: expense ratios, tax efficiency, and their own behavior. A low-cost, broad-based index fund that captures the total market will, by definition, include the losers and the winners. The mathematical beauty of this approach is that the downside of any single stock is limited to 100%, while the upside is theoretically infinite.

In conclusion, the urge to avoid big, flashy IPOs is a natural reaction to the volatility and media noise that surrounds them. However, translating that urge into a strategy of index selection is unlikely to yield the desired results. Most major indices already have safeguards in place to ensure that only viable, liquid companies are added. Furthermore, the diversification inherent in these benchmarks protects investors from the failure of any single debutante. In the long run, the discipline of staying invested in a broad market index—IPOs and all—has proven to be one of the most reliable paths to wealth creation. Trying to outsmart the index by dodging the newest names on the board is a tactical maneuver that often results in more complexity, higher costs, and the very real danger of missing out on the next generation of market leaders.

The Role of Valuation in Indexing

One of the arguments frequently cited by those who want to avoid IPOs is that these companies enter indices at ‘peak valuation.’ The concern is that an index-tracking fund is forced to buy a stock when it is most expensive, right after its public debut. While it is true that IPOs often happen during ‘bull’ windows when valuations are high, this is a feature of the market, not a bug of indexing. Market-cap weighting naturally gives more weight to companies that the market values more highly. If a company is indeed overvalued, its market cap will eventually shrink, and its influence on the index will diminish. This ‘self-healing’ property of indices is why they are so difficult to beat over long periods.

By trying to avoid IPOs, an investor is essentially making a value bet against the market’s pricing mechanism. While value investing is a legitimate strategy, attempting to execute it by switching indices is an imprecise and often ineffective method. If an investor is truly concerned about overvaluation in IPOs, they might be better served by a dedicated value-factor index rather than simply trying to dodge new listings. However, even then, the historical data suggests that the ‘newness’ of a company is not a reliable predictor of its future returns relative to its peers.

Final Thoughts for the Modern Investor

As we look toward the future, the pipeline of private companies waiting to go public remains robust. We will undoubtedly see more billion-dollar debuts that capture headlines and stir up investor anxiety. The key for the long-term investor is to see through the noise. An index is a tool for capturing the collective growth of the economy; it is not a curated portfolio designed to win every single trade. By accepting the inclusion of IPOs as part of the market’s natural evolution, investors can maintain the broad exposure and low-cost structure that make indexing so effective in the first place. Don’t let the fear of a ‘big debut’ distract you from the power of staying the course.