[gphil]

This is still the wrong math. I'm not qualified to come up with a great model here, but given that the S&P 500 has only lost value in 5 of the last 25 years the chances of having no losses in the last 25 years are a lot greater.

I've been investing for almost a decade, was lucky enough to sit out the worst in 2008, and I haven't had a down year in 10 years myself. This outcome was mostly luck on my part.

[auntienomen]

Consider the probability of beating the S&P instead. Same math applies. If that doesn't convince you, look up their monthly returns and do the same calculation.