Citibank South Dakota v State of Washington Department of Revenue. Did Citibank “engage in business activities” in Washington under former RCW 82.04.220 (1961), supporting the imposition of B&O taxes, when Citibank issued credit cards to and received income from Washington residents but did not have a business office, property, or employees in Washington? And if so, did the Department of Revenue use the correct apportionment formula in attributing Citibank’s gross income to Washington activities? Case 571277.