Since 1998, the Federal Bureau of Investigation has also maintained its own list of people who have renounced citizenship under . This is one of the categories of people who are prohibited from purchasing firearms under the Gun Control Act of 1968, and whose names must be entered in the National Instant Criminal Background Check System (NICS) under the Brady Handgun Violence Prevention Act of 1993. The names are not made public, but each month the FBI issues a report on the number of entries added in each category. NICS covers a different population than the "Federal Register" expatriate list: the former includes only those who renounce US citizenship, while the latter should include those who voluntarily lose citizenship by any means, and possibly certain former permanent residents as well.