A 1099-B is a tax form used to report gains or losses if you sold stock, bonds, or other securities through a broker or had a barter exchange transaction (exchanged property or services rather than paying cash).
Upgrade will issue a 1099-B in the event that you sold any amount of Bitcoin through your Upgrade - Bitcoin Rewards Card. To access the document, simply login to your online Upgrade account, navigate to the Statements tab and click on the Savings Tax Forms link to view your 1099-B form.