The WisdomTree U.S. Midcap Dividend Fund (DON) invests in dividend-paying mid-cap companies from within the U.S. equity market. The index is fundamentally weighted based on dividend projections for the next year, and DON carries an expense ratio of 0.38%. Investments geared towards inflation, dividends, and currency all took the top spots for flows into WisdomTree funds in the month of March.