The period after the last signal in April 2018 also saw mediocre returns. What happens if you put the two studies together?

The Dow Jones Industrial Average entered the history books Tuesday with its first nine-day losing streak since 1978. The 30-stock average slid 267.58 points, or 0.61%, to settle at 43,449.90.

But the mother of all end-of-year market chaos moments happened in a 10-day stretch to end 2018, when the Dow sank 4,000 points before staging one of the best days on record — a 1,086-point gain ...

An unseasonably bad December for the stock market just got worse. The Dow slid 620 points, or 1.4%, in Monday morning trading. The S&P 500 dropped 1.5%. The Nasdaq Composite was down 1.6%.

Futures tracking the Dow Jones Industrial Average fell 163 points, or 0.4%. The blue-chip index is riding its longest losing streak since 2018–it has fallen eight days in a row. Contracts tied ...