An investor in the $32$ percent tax bracket is trying to decide which of two bonds to select: one is a $6\mathrm{.}4$ percent U$.$S$.$ Treasury bond selling at par; the other is a municipal bond with a $5$ percent coupon, which Is also selling at par. Which of these two bonds should the investor select? Ignore state income tax.

Investor should select $$ because it has a $$ return on an after$-$tax basis.