Gun company shares soared on Monday as traders predicted that Americans will react to the Orlando massacre by rushing out to arm themselves with more guns.

Shares in the two biggest listed US gun manufacturers Smith & Wesson and Sturm Ruger & Co rose by 11% and 10% in early trading and ended the day up 6.8% and 8.5% respectively.

Gun companies shares have risen strongly after every recent mass shooting incident as investors speculate that the atrocities might lead to tougher gun control measures. Fear that stricter gun laws might be enacted cause more people to buy guns, especially semi-automatic assault rifles like the AR-15 used by Orlando killer.

Smith & Wesson, which sold a record $627m worth of guns and accessories last year, is expected to report even higher sales this year when it releases its full-year results on Thursday.

In its most recent quarterly earnings, in March, the company said sales were up 61.5%, which its British chief executive James Debney credited to the “long-term trend toward personal protection”. Sales in the quarter came in at $211m, and the company doubled its gross profit to $87m.

S&W’s share price has already rise 39% in the last 12 years, making it one of the best performing investments on the US stock markets. Sturm Ruger’s shares have risen about 6%.

On Sunday Barack Obama said the Orlando attack – “an act of terror and an act of hate” – once again showed that the nation needs to introduce tougher gun control laws. “This massacre is therefore a further reminder of how easy it is for someone to get their hands on a weapon that lets them shoot people in a school, or in a house of worship, or a movie theatre, or in a nightclub,” he said.

It was at least the 14th time that Obama has addressed the nation in the immediate aftermath of a mass shooting since he took office – and the sixth time in the last year.

After Obama’s emotional call for restrictions on assault rifles in the wake of the San Bernardino attack in California last year, Wall Street analyst Brian Ruttenbur said: “President Obama has actually been the best salesman for firearms”.

Omar Mateen, the Orlando shooter, legally purchased the .223 caliber AR rifle and Glock handgun he used in the act within the past week, a spokesman for the US Bureau of Alcohol, Tobacco, Firearms and Explosives said.

“He is not a prohibited person,” ATF assistant special agent Trevor Velinor said on Sunday. “They can legally walk into a gun dealership and acquire and purchase firearms. He did so. And he did so within the last week or so.”