IWM tracks the Russell 2000, the benchmark U.S. small-cap index, competing with Vanguard's VB and iShares' own IJR. Top holdings include names like JFrog and Moog.

Its 24.5% one-year return has notably outpaced VB's 17.4%, but at a 0.19% expense ratio — far higher than VB's 0.03%. Since the underlying small-cap exposure is broadly similar across all three, VB or IJR may be the more rational pick if cost is the priority.