BOXX offers a tax-efficient alternative to traditional money market funds for high-income investors. Each uses a different mechanism to deliver more after-tax income than a taxable money market fund. Taxes can strip a third or more from money market distributions, flipping the after-tax ranking for investors in top federal and state brackets. For an investor in a state with no income tax, the case for TFLO over a plain money market fund weakens considerably, since the federal treatment is identical. An investor comparing these funds to a money market fund yielding around 4% gross should run the math after taxes rather than on the headline.