Answer:
APY = 4.0486561%
Explanation:
Given is the Annual Percentage Rate (APR) = 3.9886% compounded quarterly.
Suppose Principal amount, P = $1.
time, t = 1 year.
interest rate, r = 3.9886% = 0.039886
period of compounding, n = 4 (for quarterly).
Future value = P * (1 + r/n)^(nt)
FV = 1 * (1 + 0.039886/4)^(1*4) = 1.040486561
Annual Percentage Growth = (FV/P)*100 = (1.040486561 / 1) * 100 = 4.0486561%
Hence, Annual Percentage Yield (APY) = 4.0486561%