The ATF estimates 10,000 ghost guns were recovered by law enforcement in 2019 alone. In December, ATF acknowledged for the first time in federal court that it is illegal to sell complete ghost gun kits without serial numbers or a background check. Credit card companies have an opportunity -- and a responsibility -- to be part of the solution by refusing to process these dangerous and illegal sales. Shannon Watts is the founder of Moms Demand Action for Gun Sense in America. This is an opinion article. The thoughts expressed are those of the author. We've made undeniable progress when it comes to keeping guns out of the hands of people who shouldn't have them. Since the mass shooting at Sandy Hook School renewed calls for sensible gun laws eight years ago, 13 states have passed laws requiring background checks on all gun sales or strengthening existing background check requirements. 29 states and D.C. have passed bills to strengthen the laws that keep guns out of the hands of domestic abusers, and following the shooting at Marjory Stoneman Douglas High School in 2018, 14 states and D.C. have passed extreme risk laws, which let family members and law enforcement ask a court to remove firearm access when there are red flags that someone poses an extreme risk to themselves or others.