is that $600 in a year? or $600 total?It is IRS requirement for them to collect SSN if your gross sales on the platform is over $600 (the threshold might go up if the latest law will pass in Congress). All payment processors are required to comply with the reporting laws - it is to ensure adequate reporting transparency. If you don't provide your SSN, you can't sell more than the required threshold on the platform - same applicable for eBay, Venmo, PayPal - any marketplace intermediary that collects and remits payments. You can read about the legal requirements online - just google IRS 1099K reporting.