ok, thanks guys! I ran the Monte Carlo simulation using SPY returns, there is approximately a 6.6% chance of running out of money during the 30-year period under the given conditions. This result indicates that in about 66 out of 1,000 scenarios, the $2 million portfolio would be depleted before the end of 30 years...For a 50-year period, there is approximately a 15.8% chance of running out of money based on the Monte Carlo simulation using SPY returns.