I do the “ETF of the Week” for MarketWatch every Thursday on Chuck Jaffe’s MoneyLife Show where I highlight big movers and disappointments within the exchange traded fund market.

This week, I looked at the Guggenheim S&P 500 Equal Weight ETF (NYSEArca: RSP).

RSP leans toward mid-cap and small stocks, which have been outperforming their blue-chip counterparts.

Click here to listen to the podcast.

The chart below shows the relative performance of Guggenheim S&P 500 Equal Weight versus the market-cap-weighted SPDR S&P 500 (NYSEArca: SPY), highlighting the recent leadership of the equal-weighted approach.

RSP is up 14.4% the past six months, compared with a gain of 8.9% for SPY.

Full disclosure: Tom Lydon’s clients own SPY.