So Top-Heavy

When you buy an index fund, you’re getting instant diversification, right?  Well, not necessarily.  And some readers may be surprised that sectoral indices are even less so.  For better or worse, almost all capitalization-weighted US equity indices and sub-indices have become quite top-heavy.

We have discussed how the S&P 500 (SPX) and Nasdaq 100 (NDX) indices have become increasingly top-heavy.  The “Great 8”, the “Magnificent 7” plus Broadcom (AVGO) make up just under one-third of SPX and a bit under half of NDX. The top 10 stocks in SPX, which adds Berkshire Hathaway (BRK.B), Lilly (LLY) and JPMorgan (JPM), while removing Tesla (TSLA), are closer to 36%; the top 10 stocks in NDX, which adds Netflix (NFLX) and Costco (Costco), indeed make up over half that index.  This hardly seems like true diversification.  Whether they want to or not, buyers of index funds linked to those indices are making a significant investment in megacap technology stocks.

Some might think, “OK, so I’ll look at specific sectors for diversification instead.”  Once again, they may be disappointed. 

[Note all weights are as of August 20^th, 2024, and the symbols that follow the sector names are those of the Sector SPDR ETFs that represent them]

Obviously, the Technology sector (XLK) would be a poor place to avoid tech, especially because Nvidia (NVDA), Microsoft (MSFT), Apple (AAPL) and AVGO, make up over half that grouping. 

The Communication Services sector (XLC) would intuitively be top-heavy with tech; Amazon (AMZN) and the two classes of Alphabet (GOOG, GOOGL) make up about 44% of that index. 

Yet despite its name, the Consumer Discretionary sector (XLY) is extraordinarily tech heavy too.  AMZN and TSLA make up about 38% of that index.  Throw in Home Depot (HD), which is at least a non-tech stock, and we have three stocks that are just under half. 

Even as we move further away from tech, we see that other sectors are quite top-heavy as well.  The Consumer Staples sector (XLP) is dominated by four companies: Procter & Gamble (PG), COST, Walmart (WMT), and Coca-Cola (KO), which comprise just under half the weight.  

The Energy Sector (XLE) is of course dominated by big oil, with Exxon Mobil (XOM) and Chevron (CHV) alone adding to 40%. 

The Materials Sector (XLB) is a surprise.  Thanks to a 21% weighting in Linde (LIN), the top four stocks, LIN, Sherwin-Williams (SHW), Freeport-McMoran (FCX), and Ecolab (ECL), comprise over 40% of that sector. 

The Financials sector (XLF) is a bit better, where the top four stocks, BRK.B, JPM, Visa (V) and Mastercard (MA) are “only” about 37% of the weight.  (By the way, the fact that three of the top four are non-banks should be a reminder that XLF is a very imperfect proxy for the banking sector.) 

The Utilities sector (XLU) might seem egalitarian, but no.  Its top four – NextEra (NEE), Southern Company (SO), Duke Energy (DUK) and Constellation Energy (CEG) – are about 35% of that sector’s weight.

Something similar applies to Health Care (XLV).  The combination of LLY, UnitedHealth (UNH), Johnson & Johnson (JNJ), and AbbVie (ABBV) are also about 35% of that sector.

The idiosyncratic Real Estate sector is not much different, with Prologis (PLD), American Tower (AMT), Equinix (EQIX), and Welltower (WELL), adding up to about a third of sector’s weight. 

Industrials is by far the most egalitarian sector.  The top four stocks, General Electric (GE), Caterpillar (CAT), RTX, and UBER, comprise a mere 17%.  In fact, the top 10 stocks only comprise about 35% of the weight.  The sector itself does not provide much diversification – it is highly dependent on economically sensitive stocks – but at least those who want exposure to industrials get it in a broad-based manner.

But most importantly, use this knowledge.  Diversification, should you desire it, is often harder to come by than it seems.