Among major U.S. indexes, the index with the highest return over the past 10 years was the "S&P 500 Top 10." As structural growth continued, led by technology corporations such as artificial intelligence (AI) and semiconductors, compressed portfolios delivered higher returns, according to the analysis.
On the 28th, KCGI Asset Management said that as of the 18th, a comparison of returns for six representative U.S. indexes — "S&P 500 Top 10," "Indxx US Tech Top 10," "Nasdaq 100," "Nasdaq," "S&P 500," and "S&P 500 (equal weight)" — showed that the "S&P 500 Top 10" index had the highest performance across all measured periods of 1 year, 3 years, 5 years and 10 years.
The "S&P 500 Top 10" index consists of the top 10 corporations by market capitalization among the U.S. S&P 500 components, posting a 1-year return of 27.1% and a 10-year cumulative return of 526.1%. It was followed by the "Indxx US Tech Top 10" index, which holds the top 10 U.S. technology corporations, at 24.4% for 1 year and 486.9% for 10 years.
By contrast, the "S&P 500 (equal weight)" index had the lowest 10-year return among the indexes analyzed, at 134.7%. The diversified effect of investing evenly across a wide range of stocks instead led to relatively lower performance in a market with a "winner-takes-all" structure.
Experts said the recent "tilt toward mega-cap tech stocks" in the market was the key factor widening performance gaps among indexes. In particular, large technology corporations such as Nvidia, Apple, Microsoft and Google sharply increased results in AI infrastructure, semiconductors and cloud, strengthening their market dominance and significantly affecting index performance.
In comparisons of the Sharpe ratio, which shows an index's risk-adjusted efficiency, indexes centered on Top 10 names also stood out. In particular, the "S&P 500 Top 10" posted the highest at 0.95 over 10 years, followed by the "Indxx US Tech Top 10." This means they recorded higher returns than the "Nasdaq" (0.82) and the "S&P 500" (0.75) at the same risk level.
In terms of volatility, the "S&P 500" was the most stable, with a 10-year standard deviation of 18.6%, followed by the "S&P 500 equal weight" (19.2%), the "Nasdaq" (22.5%) and the "Nasdaq 100" (23.0%). By contrast, the "S&P 500 Top 10" had relatively higher volatility at 23.5%, but the return gap (526% over 10 years) was judged sufficient to more than offset the volatility.