Since Mancur Olson's Logic of Collective Action (1965), it is impossible for political scientists to conceive of political participation without reference to his powerful argument linking numbers of participants, public goods, and participatory outcomes. What is puzzling is the poor empirical support for this argument in the domain where it should work best, namely explaining business political activity. Olson thought his arguments principally applicable to economic groups, and for the empirical development of his arguments Olson drew heavily on business interests, the most active segment of the interest group community. We explore these arguments with business political activities data by examining the statistical performance of various measures of market structure in determining business political activity, and find little empirical support. We do offer an alternative basis for business behavior lodged in both private and collective goods that preserves business rationality and also helps explain not only the amount of business political participation but the modes of business participation.