In 1949 the US stock market traded at about 6.8 times earnings and paid a 7.5% dividend yield — a bargain-bin valuation born of Depression-era fear. Fifty years later, at the 2000 peak, it traded near 30 times earnings with a dividend yield of about 1%. Same market, same math, almost opposite psychology.

"Stocks always win in the long run" has a real exception on the books: from the spring of 1996 through March 2020 — 24 years — long-term US government bonds returned about 8.2% a year, edging out the S&P 500’s 8.0%, and did it with roughly a third less volatility.

The worst rolling 10-year total return the US stock market has ever produced is a loss of about 40%, for the decade starting at the September 1929 peak. The best rolling 10-year return is a gain of about 597% — roughly 21% a year — for the decade starting in the summer of 1949. Same market, ten-year holding period, wildly different outcomes depending only on when you started.

Since 1928 the S&P 500 has finished the year higher about 73% of the time — roughly three years in four end in the green. Down years are impossible to predict in advance, but the base rate quietly favors staying invested.