Social Security numbers and cards are issued by the US Social Security Administration for tracking of Social Security taxes and benefits. They have become the "de facto" national identification number for federal and state taxation, private financial services, and identification with various companies. SSNs do not establish citizenship because they can also be issued to permanent residents as well as citizens. They typically can only be part of the establishment of a person's identity; a photo ID that verifies date of birth is also usually requested.