Some situations you'd need to provide your SSN include when applying for insurance through an insurance company, when applying for a loan or a credit card (or any other company that you're sending a credit application to), banks, investment advisors, and cash transactions over $10,000, such as when buying a car. Also, if you are going to college with financial aid, colleges will collect your SSN. If any other business requests your SSN, they are legally allowed to, however, it's optional. It's also optional when applying for a job at a company, but might affect your chances at getting the job depending on the employer who may want to get credit statistics on their potential employees.
