CRA indicates that reasonable efforts to obtain a TIN entail repeated attempts and should be documented, and that checking a box may be acceptable written consent to use of a TIN

S. 237(1.1) requires a “disclosing person” to provide their tax identification number to a “collecting person,” being a person who is required to make an information return under the Act. Additionally, s. 237(2)(a) requires the collecting person to make a “reasonable effort” to obtain the number.

CRA indicated that repeated attempts at the last known contact would generally be consistent with “reasonable effort,” provided the collecting person maintained adequate records of their efforts. In particular, the collecting person should keep a record of the date of the verbal or written request, an example of the request form, the names of the people contacted, and copies of any written requests. Repeatedly sending mail to the same address might not amount to a reasonable effort if the collecting person had other means of contacting the disclosing person, such as a phone number or an email address.

Regarding the offence under s. 239(2.3) to knowingly use, communicate, or permit another to use or communicate a tax identification number other than for a purpose required under the Act or otherwise by law, without the written consent of the disclosing person, CRA noted that it would generally consider this requirement to be met where the disclosing person affirmatively checks any unchecked-by-default checkbox, which is separate from or clearly distinguished from general terms and conditions, using clear and specific language describing the particular use or communication of the tax identification number in question.

Neal Armstrong. Summaries of 2 June 2026 STEP Roundtable, Q.11 under s. 237(2) and s. 239(2.3).