Credit Spread = $-\left(\frac{1}{\text{T-t}}\right)\ln\left(\frac{\text{D}}{\text{F}}\right) - r$

Where:
(T-t) = time remaining to maturity
D = current value of debt
F = face value of debt
R = risk free rate of interest

Credit Spread = $-\left(\frac{1}{10}\right) \times \ln\left(\frac{780}{1000}\right) - 0.01 = 0.01485 = 1.485\%$