National Instant Criminal Background Check System

The National Instant Criminal Background Check System (NICS) is a database operated by the FBI that licensed gun dealers must query before selling a firearm. It was created by the Brady Handgun Violence Prevention Act of 1993 and began operating in 1998.

A dealer submits the buyer's information, and the system checks it against records of people who are prohibited from possessing firearms, including felons, fugitives, people convicted of domestic violence misdemeanors, people subject to certain restraining orders, unlawful drug users and those committed to mental institutions or found mentally incompetent. Most checks produce an answer within minutes; if a result is "delayed," federal law allows the sale to proceed after three business days unless a denial arrives, a feature known as the "default proceed" that has been criticized after the 2015 Charleston church shooting.

NICS only works as well as the records it contains, and agencies have been criticized for not submitting complete records, which led Congress to pass the NICS Improvement Amendments Act of 2007 and the Fix NICS Act of 2018. Some states run their own checks. Supporters call it effective at blocking prohibited buyers, while gun-rights advocates stress false denials and the burden of appealing. NICS checks are also used as a rough indicator of gun sales. See universal background checks. See also red flag law.