"A National Security Letter (NSL) is roughly comparable to an administrative subpoena. Various intelligence agencies use NSLs to demand certain customer information from communications providers, financial institutions, and consumer credit reporting agencies under the Right to Financial Privacy Act, the Fair Credit Reporting Act, the National Security Act, and the Electronic Communications Privacy Act. Congress weighed several NSL amendments during the 113th Congress. The House passed one, H.R. 3361. The Senate failed to provide the three-fifths vote necessary for cloture on another, S. 2685. Yet in the end, the 113th Congress adjourned without enacting any of the proposed NSL amendments. […] As an additional oversight tool, S. 1215 and S. 1599 would have returned all but two of the NSL statutes to their pre-USA PATRIOT Act [Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001] form, effective June 1, 2015. The exceptions would have been the National Security Act NSL statute, which evokes few privacy concerns, and the sweeping, USA PATRIOT Act-born, Fair Credit Reporting Act NSL statute, which the bills would have repealed. This report reprints the text of the five NSL statutes as they now appear and as they appeared prior to amendment by the USA PATRIOT Act (to which form they would have been returned under S. 1125 and H.R. 1805). Related reports include CRS [Congressional Research Service] Report R40138, Amendments to the Foreign Intelligence Surveillance Act (FISA) Extended Until June 1, 2015, by Edward C. Liu, and CRS Report RL33320, National Security Letters in Foreign Intelligence Investigations: Legal Background, by Charles Doyle."
CRS Report for Congress, R43322