For instance, RSP’s largest component holding is NRG Energy (NYSE: NRG) at close to 0.3% of the fund’s portfolio.

In contrast, as a traditional cap-weighted index, the S&P 500 holds a 3.6% position in Apple (NasdaqGS: AAPL), followed by Microsoft (NasdaqGS: MSFT) 2.5% and Exxon Mobil (NasdaqGS: XOM) 1.7%. NRG also makes up about 0.3% of the S&P 500’s underlying portfolio.

Due to its equal-weight methodology, the S&P 500 Equal-Weight Index and RSP’s portfolio tilt toward more mid-sized companies. RSP includes a large 46.4% tilt toward mid-caps, followed by 40.9% large-caps and 11.8% mega-caps. In contrast, the S&P 500 includes 50.2% mega-caps, 36.8% large-caps and 13.0% mid-caps.

Moreover, due to the varying indexing methodologies, RSP is overweight consumer discretionary at 15.7% of the ETF’s portfolio and industrials at 13.8%. Meanwhile, the S&P 500 Index heavily favors information technology at 21.5%.