SIN (Social Insurance Number)

You need a SIN to be paid by an employer, to file a tax return, and to open any registered account (TFSA, RRSP, FHSA, RESP, RRIF). Banks also need it for accounts that earn interest, so the CRA gets the right T5 slip. Children need a SIN to be named as the RESP beneficiary so grants can flow. Treat the SIN like the most sensitive document you own, fraudsters who get hold of it can open credit and file fake tax returns. Service Canada will issue a new SIN if yours has been compromised.