RSP vs. SPY: Does Equal Weight Beat the Cap-Weighted S&P 500?

For investors, the decision between the Invesco S&P 500 Equal Weight ETF (NYSEARCA:RSP) and the SPDR S&P 500 ETF Trust (NYSEARCA:SPY) may appear straightforward. Both track the S&P 500, hold the same 500 companies, and come with low expense ratios. However, the weighting methodology sets them apart.

The Core Difference: Equal Weight vs. Cap Weight

SPY allocates capital based on market capitalization, meaning larger companies like Apple and Microsoft receive a higher weight. For instance, its top holding accounts for approximately 7.58% of the fund. In contrast, RSP assigns an equal weight (roughly 0.2%) to each constituent, reducing the dominance of mega-caps.

Historical Performance

Over the long term, SPY has outperformed during periods when large-cap stocks led the market, while RSP has shown resilience and better performance in environments favoring small and mid-cap stocks. SPY tends to be more concentrated in growth leaders, whereas RSP offers broader diversification.

What This Means for Investors

The choice depends on market outlook and risk tolerance. If you expect continued outperformance of mega-caps, SPY may be suitable. If you prefer diversification and lower concentration risk, RSP could be a better fit.