The S&P 500 CAPE ratio history now points to a market that has run for 17.4 years and gained 1,073% as of September 2026. Since March 2009, the index has still suffered five declines of roughly 20% or more, but most recovered quickly.
I/O Fund and the S&P 500
That is the setup behind the warning. The current advance began from the 2009 low and has already stretched well beyond the average secular bull market since 1880, which lasted 11.2 years with a 675% gain.
The comparison set cuts both ways. Since 1880, there have been seven secular bear markets, and they lasted an average of 6.7 years with an average drawdown of 52.7%, so the current stretch stands out on both length and magnitude.
Since March 2009
Since March 2009, the S&P 500 has shown a pattern of sharp pullbacks followed by fast recoveries. That matters because the market can still press higher while also carrying the kind of advance that often breeds a correction before the next leg up.
The article says the market has been tracing a standard five-wave pattern since the 2009 low. In Elliott Wave work, an ending diagonal is a five-wave structure with exceptional overlap that tends to draw a trend channel, and it appears only at the start or the end of a trend.
AI and Investors in the S
The practical read for Investors in the S is simple: the long trend is still alive, but the path higher may not come in a straight line. A correction is expected before further gains, even though the piece still allows for more upside after that reset.
How large and how soon that correction arrives is not specified. For now, the outlier is the length of the move itself — 17.4 years, 1,073%, and still counting.
