Ten companies now make up 43% of the S&P 500’s total market value, near the highest share ever recorded, according to Bloomberg data. The index still carries 500 names, but its fortunes increasingly track a handful of mega-cap technology stocks rather than the broad market its reputation promises.
The S&P 500 no longer delivers the diversification many investors assume it does. The 10 largest companies now account for 43% of the index’s total market capitalization, near the highest level ever recorded, according to Bloomberg. That figure has stayed above 40% for the past 12 months, so the shift is not a temporary spike.
The top of the index has swelled
Over the past decade, the top 10 companies have more than doubled their share of the index. The smallest 250 companies have seen their combined weighting shrink to roughly 7%, the lowest level since at least 2014.
Put another way, the market value of the largest 10 companies is now more than six times greater than that of the index’s smallest 250 members combined. That imbalance explains why a single weak earnings report from one or two mega-cap stocks can ripple through the whole market, even when hundreds of other companies perform well.
Stronger footing than the dot-com peak
This concentration does not automatically signal an imminent bear market. During the dot-com era, the largest stocks peaked at roughly 27% of the S&P 500, with companies like Cisco trading at roughly 130 times forward earnings. Today’s top 10 sit at 43%, but they also generate about 30% of the S&P 500’s total earnings, giving their leadership a stronger fundamental base than existed in 2000.
Even so, a market led by so few names has less room for error. If those mega-cap leaders disappoint, fewer stocks carry enough size to cushion the blow. That is why the author argues market breadth deserves as much attention as the headline index, and floats an equal-weight S&P 500 fund as one way to spread exposure back across all 500 names.
Source: AOL
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