Canada There is no limit on how much gold you can legally sell in Canada. What exists is a reporting rule: under FINTRAC's Large Cash Transaction Reporting requirements, dealers must report any transaction of $10,000 or more in physical cash. The report is routine and does not make the sale illegal — it is an anti-money-laundering measure.
Selling for $9,999 in cash to avoid reporting is called structuring and is itself an offence. If you sell a larger amount, simply accept payment by cheque or bank transfer, or expect the dealer to file the standard report.
Expect to show government-issued photo ID when selling precious metals. Dealers are required to verify your identity for large transactions and many record it for any purchase, and most provinces require pawn and second-hand dealers to keep seller records.
Profit from selling investment gold is a capital gain: 50% of the gain is added to your taxable income in the year you sell. Keep your purchase receipts — without them, proving your cost base to the CRA is harder.
GST/HST is generally not charged on investment-grade bullion (99.5%+ purity for gold and silver) when you buy it, and you do not charge GST/HST when you sell as a private individual. Jewellery and lower-purity items follow different rules — confirm with the CRA or a tax professional for large sales.