In 2006 agency bonds sold at a yield of 5.32%, while high-grade tax-exempts of comparable maturity offered

Question:

In 2006 agency bonds sold at a yield of 5.32%, while high-grade tax-exempts of comparable offered 3.7% annually. If an investor receives the same after-tax return from corporate and tax-exempts, what is that investor's marginal rate of tax? What other factors might affect an investor's choice between the two types of securities?
Maturity
Maturity is the date on which the life of a transaction or financial instrument ends, after which it must either be renewed, or it will cease to exist. The term is commonly used for deposits, foreign exchange spot, and forward transactions, interest...