There are two bond investment opportunities available to you:

Option 1: Corporate bond yield to maturity (return) is 5.16%

Option 2: Municipal bond yield to maturity (return) is 4.42%

Assume your marginal tax rate is 23.79%.

What is the equivalent tax-free rate for the corporate bond?

Please round your answer to the fourth decimal. If your answer is 1.23%, you should input 0.0123 instead.