Tri-Met current rate is .006195. Lane transit current rate is .006. If you have more than one business activity, the loss from one business cannot offset the profit of another business. A supporting schedule showing the profit or loss from each business will need to be submitted with the one return that a taxpayer is required to file.
Insurance agents are exempt from the self-employment tax.
Real estate sales people generally are considered self-employed under federal law. You must file on a calendar-year basis. I don't live in the Tri-Met or Lane transit district, I don't ride the bus, and my customers don't ride the bus. If you perform services in the district or make sales to customers within the district, you are subject to the tax. Multnomah, Washington, and Clackamas are the three counties within the Tri-Met district boundary.