How does the BC PTT 20% Foreign Buyer Additional Tax stack with the federal Foreign Buyer Ban?

Direct answer

They do different things and can BOTH apply to the same transaction. The federal Prohibition on the Purchase of Residential Property by Non-Canadians Act ("Foreign Buyer Ban") is a PROHIBITION — a non-Canadian who is not exempt cannot enter into a new purchase contract for covered residential property in CMAs/CAs at all. The penalty for breach is up to $10,000 + a court-ordered sale at no profit. BC's 20% Additional Property Transfer Tax (APTT) is a TAX — it applies at registration to a non-Canadian who is otherwise federally permitted to purchase (e.g., a presale signed before January 1, 2023 that completes today; a Canadian-citizen-spouse joint purchase prorated to the foreign spouse's share; or any covered exemption holder). Worked example: a non-Canadian with a Canadian-citizen spouse buying a $1.5M Vancouver condo 50/50 — federal exemption permits the purchase (no fine), but BC APTT applies on the 50% foreign share = 20% × $750K = $150K, on top of standard PTT of $28K. Total tax: $178K. Worked example #2: a non-Canadian with no exemption who breaches the federal Act and somehow registers — they face the $10K fine + court-ordered sale AND BC APTT of 20%. The federal and provincial regimes do not "credit" each other; they layer.