FXN doesn't aim to represent the broad US energy space. Instead, it tries to pick winners by employing a quant-based model and tiered equal-weighting scheme. The resulting portfolio is heavily tilted toward mid-caps. The fund also comes with heavy industry tilts, away from large integrated oil & gas companies, and overweights smaller-cap industries such as drilling & exploration. The resulting beta is relatively risky but understandable in light of the funds strategy. The index is reconstituted and rebalanced on a quarterly basis.