CRA indicates that a supply is deemed for GST/HST purposes to be received by a recipient at the time the related agreement is entered into

ETA s. 133 deems property or services supplied pursuant to an agreement to be supplied at the time the agreement is entered into. It does not explicitly deem there also to be an acquisition by the recipient at that time, but this appears to be inferred by CRA.

Where a builder was invoiced, after the time that it self-assessed for the fair market value of a newly-constructed multiple unit residential complex (at the time of substantial completion and first tenant occupancy) for work done before that time, CRA explained the availability of an input tax credit therefor on the basis that, by virtue of s. 133:

where a builder of a MURC agrees to acquire property or a service for consumption or use in constructing the MURC, the supply of the property or service is generally considered to be made to the builder at the time that the agreement is entered into (that is, the builder is considered to be the recipient of the supply at that time).

Neal Armstrong. Summaries of May 2019 CPA Alberta CRA Roundtable, GST Session – Q.8 under ETA s. 133 and s. 169(1).