These are the telecommunication companies that, by order of the Foreign Intelligence Surveillance Court, must provide to the NSA telephone metadata for all calls originating or terminating in the United States, as described in a Jan. 3, 2014 FISA court order.

Here, the Obama administration explains Reasonable Articulable Suspicion, a standard by which the government may query the trillion-plus metadata phone records to combat terrorism, as outlined in a Feb. 5, 2014 FISA court filing.

This page identifies those being targeted for surveillance of electronic communication such as email, despite allegations that the NSA wrongly scooped up "tens of thousands" of such communications by American citizens, as detailed in a Oct. 3, 2011 FISA Court order.

Here is a page noting the "sole purpose" of the bulk telephone metadata program, as described in a August 29, 2013 FISA Court opinion.

This FISA court opinion from March, 2009, cites the number of metadata records the NSA receives "per day," and explains what they don't pertain to.

Here are the docket numbers referenced in what is believed to be the first FISA court opinion authorizing the bulk telephone metadata program, as included in a May 24, 2006 FISA court opinion.