SILJ tracks an index of companies from around the world that derive revenues from silver mining, have market share of global silver production, or are engaged in exploration/development related to silver production. To determine their silver revenue percentage, securities are assigned a Metals Focus sector (e.g., Project Development, Silver Mining, Streaming, Diversified Mining, Gold Mining, etc.). The fund calculates for a theme-adjusted free-float market value for each security based on their market cap and Metals Focus. The fund overweights pure-play companies, as the initial weights are determined by the securitys theme-adjusted free float market value divided by the aggregate value of all securities. It is then adjusted based on their market cap, subject to constraints. The index is reconstituted semi-annually and rebalanced quarterly. Prior to Jan. 29, 2024, the fund was called ETFMG Prime Junior Silver Miners ETF that tracked the Prime Junior Silver Miners & Explorers Index.