gbell415, welcome to the forum. Most of the mystery shopping companies that you sign up with will require your social security number. Some will allow you to sign up without providing the social security number immediately, but if you perform a job for them, you will have to provide it in order to get paid. I have provided my social security number to all companies that I currently work for. I always make sure I sign up on a secure website and that I sign up with only legitimate companies. Below, the blue link at the bottom of the page, Official List of Mystery Shopping Companies, is a great list of legitimate companies.