IWM is among the best choices in the crowded US small-cap field. The fund tracks the popular Russell 2000 index. IWM's broad basket makes it one of the most diversified funds in the segment. Notably, the fund delves into micro-cap territory, and has often been riskier than our neutral benchmark (as measured by beta) as a consequence. However, including micro-caps is a valid and possibly desirable approach to small-caps, and IWM looks reasonably similar to the benchmark in most other respects.