The only Social Security number (SSN) you should ever use is your own. Using a fake number, or a number belonging to another person, is a form of perjury and fraud that is punishable under federal law. The circumstances under which you use a fake SSN can result in enhanced penalties.

Penalty for Perjury

Many documents you sign that include your SSN for identification purposes usually includes a statement that you are signing under the penalty of perjury. A conviction for perjury can carry a five-year prison sentence and a fine of $40,000 under U.S. Code 18 U.S.C. 1621.

I-9 Fraud

Providing a fake SSN to an employer when providing information for an I-9 form can result in a five-year federal prison sentence and a maximum fine of $250,000.

Bank Fraud

If you use a fake SSN to obtain a loan from a federally chartered bank (which many are), you can be convicted of bank fraud under U.S. Code 18 U.S.C. 1334. Prison time for this crime ranges upwards of 30 years, and the fine can be as high as $1 million.

Identify Theft

Using a fake SSN could also be prosecuted as identity theft if the number turns out to belong to another person. This is punishable under federal law as well and carries a maximum sentence of 15 years, under 18 U.S.C. 1028.

State Law Penalties

Even if your use of a fake SSN does not catch the attention of the federal authorities, each state has its own laws against misuse of identifying information, which can result in penalties ranging from a fine to probation and imprisonment.

Source:

18 U.S.C. 1621: Perjury

Florida Attorney General: Federal ID Theft Law

Federal Sentencing Guidelines Calculator