When Should I Give Out My Social Security Number?Social security numbers are frustratingly insecure. It’s a vital piece of personal information that you’re supposed to keep secret, but you also constantly have to use it to identify yourself. It’s easy to see why identity theft is one of the fastest-growing crimes in the U.S., with consumers losing about $16 billion to identity theft and fraud in 2016. In addition to freezing your credit and signing up for identity theft protection services, a key part of protecting your personal information is knowing the answer to the question, “When do I need to give out my social security number?” The right choice isn’t always obvious, so read on to learn more.

When should I give out my social security number?

Your social security number, or SSN, is tied to a set of data that is very important to the government: your taxes. Your tax identification number and your SSN are one and the same by default, and the Internal Revenue Service often uses your SSN to track what taxes you owe. When you’re filling out forms dealing with the IRS, or any government agency that handles benefits such as food stamps, disability insurance and Medicare, you have to put down your SSN. You’ll also need it when you get hired at a new job, as your employer has to report your financial information to the IRS. More situationally, if you make a payment of $10,000 or more using cash, cashier’s checks, bank drafts, traveler’s checks or money orders, the person (or entity) you paid has to record your SSN, as the IRS requires merchants to fill out a special form if they make any cash transactions of that size. So, if you buy a car in cash, don’t be surprised when the dealer asks you for your number.

In addition to taxes, your social security number is used by credit bureaus to monitor your credit history. That means anytime you need to get a credit check, such as when you’re applying for a loan or an apartment, you have to hand over your SSN. Similarly, you’ll need to enter your SSN if you check your own credit reports. Typing your SSN into a website is risky, as there are many fake websites littering the Internet, so before you do, make sure the credit reports site you’re on is a legitimate one like AnnualCreditReport.com, and check to see that your connection is secured with HTTPS.

Apart from that, U.S. security laws add a few more situations where you’ll need to provide your social security number. The first comes from Section 326 of the PATRIOT Act, which aims to curb money laundering by requiring SSNs for anyone who tries to open a bank account or merchant account. The second is a part of the REAL ID Act, which added the social security card to the list of documents necessary to obtain a driver’s license or identification card. Finally, Section 111 of the Medicare, Medicaid and SCHIP Extension Act of 2007 orders all health insurance providers to send SSNs to the Centers for Medicare & Medicaid Services, so if you’re talking to your issuer about changing your health plan, you’ll have to give them your number.

When shouldn’t I give out my social security number?

First, as a general rule, you shouldn’t give your social security number out over email, or over the phone if you didn’t initiate the call. If someone emails or calls you asking for your entire SSN, it’s almost definitely a scam, as financial institutions and government agencies both recognize that as an unsafe practice. Even when you’re the person who initiated the call, you should still try to only give out the last four digits of your SSN, and before that, ask if you can provide an alternative form of identification instead.

On to more specific situations, one place where people are often unnecessarily asked for their social security numbers is doctor’s offices. There’s no law mandating you give your SSN to your doctor, so when you’re filling out a medical form and you get to the section for your SSN, try to just leave it blank. Unfortunately, there are a couple cases where you do need to provide your SSN to your doctor. Some health insurance companies identify their policyholders by their SSNs, so if your insurance company does that, you’ll have to give your number or your doctor won’t get paid. Another exception is people on Medicare who have older cards, as the Health Insurance Claim Number on older Medicare cards is based on the cardholder’s SSN. The government is currently replacing all of the old Medicare cards with new ones that use unique numbers not tied to Social Security, but the rollout for those won’t be finished until April 2019.

People are also sometimes asked to provide social security numbers when booking travel, such as flights and cruises. America may have stringent airport security, but your SSN is not something you have to provide as long as you have the proper forms of photo identification. If you don’t have the right ID to get through security, you can voluntarily give a Transportation Security Administration agent the last 4 digits of your SSN so they can check government databases to verify your identity, but this isn’t a requirement. However, note that airlines in foreign countries may ask you for your SSN because the laws differ, and if you encounter this, you should read the airline’s terms of service or call its customer service line to see if there’s an exception for international passengers.

Additionally, if you have kids, you may be asked to provide your child’s social security number on camp or school forms. Child identity theft is a serious issue, and in many cases you don’t have to put your child’s SSN down. SSNs are not necessary for school enrollment by law, and extracurricular activities often ask for a SSN just to establish proof of identity, which a birth certificate also accomplishes.

There are probably plenty of other situations where you’ll be asked for your social security number when you don’t really need to give it, so when in doubt, ask why the organization you’re dealing with needs your social security number, what will happen if you don’t give it and if there are any laws requiring you to give your number in this circumstance. You can find more tips for keeping your personal information safe by following our identity theft protection blog.