Randall Forsyth of Barron’s reminds us that the stock market has a tendency to weaken at this time of the season.

[T]here have been an unusual number of market upheavals around this time. A partial list includes a panic that shut the New York Stock Exchange in 1873; Britain’s exit from the gold standard in 1931; and the Plaza Accord in 1985, which led to the attempt to stabilize exchange rates, which came unraveled two years later and, in turn, led to the October 1987 crash.

Other early-fall market plunges occurred in 1978 and 1979, along with the Long-Term Capital Management–related plunge in 1998. And the crash of 1929 and the financial crisis of 2008 are major events, not just in market lore, but in the nation’s history, as well.

Given this treacherous season, it’s perhaps not so surprising that global stock markets once again were in full swan-dive mode at the end of last week. Yet, more than the time of the year appears to have caused equities to retreat.

On form, stocks ought to have been rallying on the seemingly bullish news that the Federal Reserve decided not to initiate the liftoff in interest rates. The continuation of the near-zero rate policy put in place in December 2008, during the darkest days of the financial crisis, should have been good news for risky assets, whose values have been boosted by investors’ flocking after anything, which is better than the nothing that they get on their cash.

Still, the stock market’s response—surrendering initial gains on Thursday afternoon in the U.S. after the Fed’s stand-pat announcement and plunging worldwide on Friday—suggests that investors sense something less than salubrious in the actions of Fed Chair Janet Yellen and her cohort on the Federal Open Market Committee.