SAN FRANCISCO (Reuters) - Background checks related to U.S. firearm purchases suffered their deepest quarterly decline in over three years in July, suggesting a sales slump despite price discounts aimed at improving customer demand following President Donald Trump’s election.

FILE PHOTO: A selection of Glock pistols are seen for sale at the Pony Express Firearms shop in Parker, Colorado December 7, 2015. REUTERS/Rick Wilking/File Photo

Fears that Democratic candidate Hilary Clinton would win the election and limit gun sales led to record purchases last year, but Trump’s surprise victory has had a reverse effect, with 2017 sales falling and investors selling gunmaker shares.

U.S. Federal Bureau of Investigation background checks in July fell 25 percent to 907,348, according to the National Shooting Sports Foundation. That was the worst year-over-year decline in background checks since November 2013, a year after Democratic President Barack Obama won his second election.

(For a graphic, see: tmsnrt.rs/2hv75dS)

Background checks are a strong proxy for monthly gun sales, whose figures manufacturers do not publicly release.

Reflecting lower demand for guns, Sturm Ruger & Company Inc RGR.N on Thursday reported revenue for the quarter ending on July 1 down 22 percent at $132 million. The company said the drop was due to unusually strong demand last year related to the Nov. 8 election.

During the second quarter, shops bought fewer guns as they worked through existing inventory, and revenues also fell as other manufacturers offered rebates, Sturm Ruger said.

Also on Thursday, sporting goods retailer Cabela's Inc CAB.N posted a 4.2 percent decrease in quarterly revenue.

“Since the fall election, we have continued to see a slowdown in firearms and shooting related categories,” Cabela’s Chief Executive Tommy Millner said in a statement.

Millner also pointed out that the quarter came a year after a mass shooting at a nightclub in Orlando, Florida, which led to an increase in gun sales due to worries that about potential new gun restrictions.

Shares of American Outdoor Brands Corp AOBC.O, the owner of Smith & Wesson, hit all-time highs last year. But since the election, the stock has fallen 30 percent, while Sturm Ruger has lost 17 percent. Ammunition seller Vista Outdoor Inc VSTO.N has dropped 41 percent.

The National Shooting Sports Foundation strips its background checks data of applications for conceal-carry permits, typically made by people who already own guns, to give a better reflection of actual purchases.

Sturm Ruger and Vista Outdoor both rose over 1 percent on Friday but were down for the past week by 7 percent and 2 percent, respectively. American Outdoor Brands was down 1.1 percent on Friday and 3 percent lower in the past five sessions.