Eerily calm

If a run to a record for the stock market could ever be boring, this is it.

The Standard & Poor’s 500 index closed Wednesday at yet another all-time high, the 27th time it’s done that this year. The strong performance has helped 401(k) accounts swell even bigger, but investors can be forgiven if they haven’t noticed much. This year’s ride higher has been a remarkably quiet one.

The S&P 500 has had just four days this year where it’s swung by at least 1 percent, up or down.

That’s way fewer than normal.

Over the last 50 years, the index has typically had 54 such days in a year. If this year’s pace continues, it could end 2017 with the fewest such days in more than 50 years.

To many wary investors, such equanimity is actually unnerving. They worry that a ride this smooth can’t last, will eventually get back to historical norms and possibly overshoot on the way.

The calm market may be partly the result of all the extraordinary stimulus central banks have unleashed since the financial crisis, but the Federal Reserve is now raising interest rates and others are talking about ending their bond-buying programs. So, enjoy this calm while it lasts.

The last time the S&P 500 had this calm of a year was in 1965, when it had 8 days where it swung by 1 percent. That actually followed an even more-quiet year. In 1964, the index had only 3 such days.