New York CNN Business  — 

Stocks of publicly traded gun companies rose Monday, following calls for stricter gun laws after two more deadly mass shootings in the United States over the weekend.

Shares of American Outdoor Brands (AOBC), formerly known as Smith & Wesson, rose 3% while Sturm, Ruger (RGR) & Co. was up 2%, even as the broader market plunged on growing trade tension between the United States and China. Vista Outdoor (VSTO), a maker of ammunition, also gained slightly.

President Trump said in a tweet Monday that “Republicans and Democrats must come together and get strong background checks” following the killings at a Walmart in El Paso, Texas, and near a bar in Dayton, Ohio.

Gun stocks tend to rally after lethal massacres, because investors think the prospect of stricter gun laws will lead people to rush out and buy more weapons and ammunition in anticipation of tougher regulations.

The surge in gun companies’ stocks following mass shootings were generally more pronounced after shootings that took place when President Obama was in the Oval Office. Obama was a Democrat who advocated for more stringent laws. By contrast, President Trump was endorsed by The National Rifle Association, a powerful lobbying group.

As the number of mass shootings have increased in recent years, the calls for tougher gun laws have grown somewhat more bipartisan.

The CEO of sporting goods retailer Dick’s (DKS) decided to ban the sale of assault weapons. There are growing calls for Walmart (WMT) and other retailers to do the same.