What will be my proof of ownership for RTB? February 28, 2020 02:47 Updated You will receive your Confirmation of Sale (COS) via email within 30 days after issue date. Related articles Can I order RTB anytime? Retail Treasury Bonds Due 2028 (RTB 28) FAQs How much is the broker’s fee for RTBs? Where do I get the interest payments of RTBs? How often? How to buy RTBs thru FirstMetroSec?