A services recipient’s contracting address is “most closely connected” with the supply for GST/HST place-of-supply purposes

A supply of services generally is made for HST purposes in the province corresponding to the home or business address of the recipient obtained by the supplier in the ordinary course of business – or, where there is more than one such Canadian address, then the address which "is most closely connected with the supply."  CRA has stated, more clearly than in some previous interpretations, that "the business address of the recipient from which the supplier is hired pursuant to the agreement for the supply (the "contracting address") is generally the address that is most closely connected with the supply."

Neal Armstrong.  Summary of 3 February 2014 Interpretation 126057 under New Harmonized Value-added Tax System Regulations, s. 13(1).