The number of federal gun background checks fell 12 percent in February to their lowest level for the month in four years, surprising industry analysts who said the numbers indicate the market hasn’t completely shaken its “Trump slump.”

The FBI ran slightly more than 2 million checks through the National Instant Criminal Background Check System (NICS) last month, compared to more than 2.3 million in February 2018.

“The large year-over-year drop in February 2019 sales, particularly in the long-gun segment, might give the industry some pause,” said Jurgen Brauer, the chief economist at Small Arms Analytics.

One explanation could be that last year’s numbers were particularly high, in the wake of the Valentine’s Day shooting in Parkland, Florida.

Background checks have historically surged in the aftermath of prominent mass shootings, and it could be that a post-Parkland surge has since worn off, said Robert Spitzer, a professor at SUNY Cortland.

“We’ve seen that phenomenon after Sandy Hook and after some other recent mass shootings as well, where gun owners will deliberately go out and buy a gun two weeks after the shooting to make a political statement,” said Mr. Spitzer, who has written extensively on the politics of gun control.

Data suggest there was a “Parkland effect” on sales last year that stretched into March.

Overall, the 2.3 million checks in February 2018 were only 4 percent higher than a year earlier. But there were also close to 700,000 checks run between Feb. 26 and March 4 of last year — the eighth-highest weekly total ever, according to the FBI.

The effect appeared to really take hold last March, when there were 2.77 million checks — up nearly 14 percent from March 2017.