Despite the name recognition that comes from tracking the Dow and its own popularity, DIA is not the ideal ETF for investors who want broad-based exposure to US large-caps. The fund's tiny portfolio, arbitrary selection, and antiquated weighting produce significant sector biases relative to the market and cover only a fraction of the large-cap space, typically represented by hundreds of names. Stocks are price-weighted, not cap-weighted, which can produce major sector realignments when multiple holdings change. Still, DIA tends to move with the broader market day-to-day, and some may prefer its typically (slightly) lower beta. DIA is extremely liquid, with huge assets and a long track record. The fund's UIT structure is shared by a few other long-lived ETFs, with the most notable effect being a slight cash drag since dividends received can't be reinvested as is typically the case. UITs must also hold every stock in the index at all times, which can tie the portfolio manager's hands.
