The Dow Jones Industrial Average and the S&P 500 were on the nice list again this year. The Dow ended Tuesday at 36799.65, a new record close and up 2.4% from Dec. 23, marking the index’s best Santa rally since the period ending in January 2009, according to Dow Jones Market Data. The S&P 500 rose 1.4% from Dec. 23, its best Santa rally since January 2013. The tech-heavy Nasdaq Composite, however, fell 0.2%. All three indexes rose in the previous five Santa periods.

All three indexes fell Wednesday, after the Federal Reserve released minutes from a recent policy meeting.

Historically, the S&P 500, the Dow and the Nasdaq Composite have risen during the Santa period about 80% of the time. The Dow’s average gain has been 1.4%; the S&P’s 1.3%. The Nasdaq Composite has risen 1.8% on average.

One theory for the gains: Lower-than-average trading volume during the holiday season can lead to more volatile trading. Some money managers also adjust portfolios to end the year.

Though some investors watch it mostly for fun, a Santa rally can set the tone for the trading year ahead.

Sometimes, Santa doesn’t bring gifts to Wall Street. Since December 1999, the S&P 500 fell during the Santa period five times. Each time, the following January finished lower, according to

Ryan Detrick,

chief market strategist for LPL Financial. Three times, the S&P finished lower for the year: 2000, 2008 and 2015. “We do not think this is a metric that investors should simply ignore,” Mr. Detrick said.

U.S. stocks had a banner 2021, with the S&P 500 advancing 27%. Though the Omicron variant threw stocks into a tailspin on Black Friday, the S&P 500 and the Dow recovered quickly. Both notched multiple new records afterward, including into this week.

But many investors see a rockier path ahead for stocks in 2022. Strong corporate earnings growth is expected to slow. Fast inflation could weigh on consumer spending. Tech stocks drove a majority of the market’s 2021 gains, but expected interest-rate increases could make them less appealing.

Mark Hackett,

chief of investment research at Nationwide Investment Management Group, said it wouldn’t be surprising if the S&P 500 recorded more normalized returns in mid-single digits in 2022.

“It is unrealistic for anybody to talk about [returns] being a mirror image of last year,” said Mr. Hackett, who recommends investors hold equities over bonds. “We can’t continue these abnormally high returns.”