Sepehr Shahshahani and Nolan McCarty have posted this draft on SSRN (forthcoming, NYU Law Review). Here is the abstract:

Observers fear that large corporations have amassed too much political power. The central fact that animates this concern is growing economic concentration—the rise in the market share of a small number of top firms. These firms are thought to use their enhanced economic power to capture the government and undermine democracy by lobbying. Many scholars and activists have urged the use of antitrust law to combat this threat, leading a “political antitrust” movement that advocates explicit incorporation of political considerations into antitrust enforcement. Political antitrust has sparked great debate not only in academic circles but also among policymakers.

But the debate has been largely data-free; there is little systematic evidence on whether increased economic concentration leads to democratic harms in established democracies. In this Article, we fill that gap, bringing systematic data analysis to bear on the issue for the first time. We make three contributions. First, we create a comprehensive dataset on lobbying of the U.S. federal government, capturing nearly one million records over the past two decades. Second, we use our dataset to map lobbying patterns, focusing on the connection between economics and politics. Third, we empirically test some postulates of political antitrust.

Our findings do not support the political antitrust movement’s central hypothesis that there is an association between economic concentration and the concentration of lobbying power. We do not find a strong relationship between economic concentration and the concentration of lobbying expenditure at the industry level. Nor do we find a significant difference between top firms’ and other firms’ allocation of additional revenues to lobbying. And we find no evidence that increasing economic concentration has appreciably restricted the ability of smaller players to seek political influence through lobbying. Ultimately, our findings show that the political antitrust movement’s claims do not rest on a solid empirical foundation in the lobbying context. Our findings do not allay all concerns about transformation of economic power into political power, but they show that such transformation is not straightforward, and they counsel caution about reshaping antitrust law in the name of protecting democracy.