Donald Trump’s first 100 days as U.S. president are now underway, and one strategist has highlighted how stocks have fared historically during a new president’s initial months on the job.

Since 1953, the S&P 500 SPX, -0.84% has gained 1.6% on average during the first 100 days of a new commander-in-chief’s first term, said Sam Stovall, chief investment strategist at CFRA, in a note Wednesday.

“Critics and investors give the president and his team a 3+ month grace period enveloped in optimism,” Stovall wrote.

However, Trump might not enjoy a honeymoon, given how the S&P typically has behaved for GOP politicians as they settle into the White House.

“Performance differences by party were pronounced,” Stovall said. “The S&P 500 fell in price an average of 0.4% under the five new Republican presidents, and rose 60% of the time, versus a 3.5% average gain and an 80% frequency of advance for the six Democrats.”

The CFRA strategist’s findings are presented in the table below.

How stocks perform in a new president’s first 100 days

S&P 500's average % change Higher what % of the time All new presidents' first 100 days +1.6% 70% New Republican presidents' first 100 days -0.4% 60% New Democratic presidents' first 100 days +3.5% 80%

Source: CFRA/S&P Global data for new presidents since 1953

To be sure, the stock market’s action after Friday’s swearing-in ceremony doesn’t have to follow any script. Stovall often has said that history is only a guide and “never gospel.”

Before Trump’s first 100 days began, the S&P SPY, -0.88% logged its biggest election-to-inauguration gain since Bill Clinton won a second term in 1996.

Another theme has been strategists backing a sell-the-inauguration strategy, as MarketWatch has noted here and there.

See:Here’s an apolitical reason Trump won’t deliver Obama-sized gains

Meanwhile, Citi analysts have offered a chart for what could happen next in terms of new policies:

Check out:Country music stars ride to rescue of Trump’s inauguration

White House disputes inauguration crowd estimates

This story was first published on Jan. 19, 2017.