Business and Occupation Tax. Washington's major business tax is the business and occupation (B&O) tax. B&O tax is improsed on the gross receipts of business activities conducted within the state, without any deduction for the costs of doing business. Businesses must pay the B&O tax even if they do not make any profits or are operating at a loss. A taxpayer may have more than one B&O tax rate, depending on the types of activities conducted. Major B&O tax rates are 0.471 percent for retailing; 0.484 percent for manufacturing, wholesaling, and extracting; and 1.5 percent for services, and activities not classified elsewhere.