In a big announcement Thursday, Guggenheim Investments revealed it would reduce the management fee of the $13 billion Guggenheim S&P 500® Equal Weight ETF (NYSEArca:RSP) from 0.40% to 0.20%, effective June 30.

Introduced in 2003, RSP is the industry’s first strategic or “smart” beta ETF, offering investors equal weight exposure to all stocks within the S&P 500® Index—widely regarded as the best gauge of large-cap U.S. equities.

“This significant fee reduction is designed to benefit existing shareholders and acknowledge the increasing use of RSP by institutional and individual investors as a core equity holding,” said Douglas Mangini, Senior Managing Director and Head of Intermediary Distribution.

The combination of balanced exposure to all S&P 500 Index stocks with a disciplined quarterly rebalance has led to RSP’s outperformance over the cap-weighted S&P 500® Index since the fund’s inception in both cumulative and average annual returns.

In fact, RSP has outperformed the S&P 500 in 100% of all monthly rolling 10-year time periods.

The underlying concept was a simple one. RSP would equally weight each of the 500 stocks in the S&P 500 Index, ensuring that the smaller names within the Index were weighted as heavily as the larger names.

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The equal-weight approach was implemented to eliminate the large-cap bias of traditional capitalization-weighted index products. The resulting reduction in concentration risk, combined with a quarterly rebalance, has helped RSP consistently outperform the S&P 500 on a rolling monthly basis since the fund’s 2003 inception.

RSP is available through most broker-dealer firms and on several major no-transaction-fee platforms. Guggenheim Investments is the global asset management and investment advisory business of Guggenheim Partners.