When applying for an American Express card, it asks me for my social insurance number (SIN) but it is optional. Should I give it? The site states

We encourage providing your SIN for more accurate identification (e.g. obtaining your credit bureau report).

As an aside, I remember when I got my SIN card I was told it is confidential and to keep it a secret. I can think of lots of things that ask for your SIN quickly, for example some job openings ask for it along with the pre-screening questions. What bad things can someone do with your SIN?

  • Once I applied for an apartment and they asked for my SIN; I declined. She told me "without that we can't confirm you've never been in jail." True? I don't know. Jun 5, 2021 at 14:56
  • I don't think a SIN gives access to your criminal record. Jun 5, 2021 at 19:04
  • Interesting. Some places I worked used the SIN as a password for clocking in.
    – Latchar3
    Jun 5, 2021 at 23:28

1 Answer 1


According to the Canadian government SIN code of practice

Never give out your SIN unless you are sure it is legally required or you are satisfied it is necessary.

In the private sector, you must provide your SIN to your employer for income tax and benefit purposes. You must also give it to financial institutions for accounts that pay interest. Except when required for government programs and services, it is your decision when to share your SIN information and with whom.

If you are not satisfied that it is necessary (meaning you think it is not necessary or you are not sure) don't give it out.

I believe a company cannot require you to give a SIN in order to give you a service. The fact that Amex says it is optional suggests they know that.

  • "Never give out your SIN unless you are sure it is legally required or you are satisfied it is necessary." the whole question is when is it nescecary?
    – Latchar3
    Jun 5, 2021 at 23:26
  • It doesn't say "give it out when it is necessary" it say "only when you are satisfied that it is necessary". If you aren't sure you shouldn't give it out. For myself I give it out only when legally necessary. Jun 8, 2021 at 21:17
  • @Latchar3 the quote lists the two times it is necessary in the private sector: to an employer that pays you salary and benefits, and to a financial institution that pays you interest. That is all. For example a vendor (Eg a daycare) to whom you pay money you're going to deduct from your taxes does not need your SIN. Your landlord doesn't. Your creditors don't. It's not necessary. Jun 10, 2021 at 19:46

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