The political economy of U.S. lobbying centers around the prevalence of large corporations’ individually targeting of legislators. Does this extend to a similar economy with similar lobbying rules, or is this predominance of corporate lobbying particular to the U.S.? We examine this question for the first time by comparing firm and association lobbying in the U.S. and Canada regarding the United States-Mexico-Canada Agreement (USMCA). We argue that the concentration of policy leverage on the executive rather than the legislative branch, and tighter constraints on corporate donations compared to the US, would produce distinctive patterns of lobbying in Canada. Corroborating this idea, we find notable differences in the lobbying patterns across the border. Within the same industries, access to the executive is prioritized in Canada and trade associations play a relatively larger role. The findings broaden our understanding of the role of political institutions for producer mobilization in the two countries, and demonstrate the relative importance of legislators and corporations as unique features of the American political system.