Given Company PQR, which has issued a 1-year maturity zero-coupon bond with a face value of USD 2,000,000, and this bond is observed to be trading at 75% of its face value currently, calculate the estimated 1-year risk-neutral probability of default. Please note that there is no recovery rate in the event of default. The only factor contributing to the excess spread is credit risk. Additionally, the continuously-compounded risk-free interest rate is 3% per annum. Employ the risk-neutral binomial tree methodology to determine the probability of default.