How is political representation shaped by dramatic economic change? This paper considers the consequences of expanding overseas trade for parliamentary representation during England's long 17th century, the period in which new trade routes between Western Europe, Africa, Asia and the Americas were opened. To date, one of the significant challenges in addressing this question has been the lack of availability of sub-national measures of overseas trade. Using data derived from the archival Port Books, records of customs collections for overseas voyages, this paper measures port-specific annual trade over the centuries-long scale it expanded. Paired with data on contests for parliamentary office, and the characteristics of both challengers and representatives, the paper uses a series of difference-in-differences designs to evaluate the consequences of expanding trade for competition for political power and the entry of new economic elites to Parliament. The paper finds that trade generated little new competition for parliamentary office, even while parliamentary representation shifted towards elites involved in new trades. Rather than compete against old economic elites, new economic elites arose directly from their ranks, capturing the benefits of trade to persist in power. Overall the paper demonstrates how representation can be responsive to economic change, even when that change does not arise via open, adversarial competition for political office.