You’ve Got Mail! The Late 19th Century U.S. Postal Service Expansion, Firm Creation, and Firm Performance
利用加州历史数据，研究发现19世纪末美国邮政扩张促进了新企业创建，主要通过传播专业知识而非金融服务，且对依赖专业知识的企业帮助更大。
This paper examines the impact of the expansion of the U.S. Postal Service in the late 19th century on firm creation and performance. Utilizing newly digitized archival data on historic business establishments, post office locations, and road networks in California, our study identifies a positive relationship between the expansion of the Postal Service and the emergence of new firms. To address endogeneity concerns, we leverage an unexpected change in the Postal Service route network. Our findings suggest that the Postal Service played a significant role in facilitating firm entry by acting as a carrier of specialized knowledge rather than as a financial service or mass communication infrastructure. We further reveal that, although increased competition from new entrants generally exerted downward pressure on incumbent firms, those relying on specialized knowledge and public technology inputs significantly benefited from local Postal Service access. Taken together, our study underscores the critical role played by the Postal Service in knowledge diffusion and local economic development by enabling the sourcing of specialized knowledge and technologies from other geographies. Overall, our results contribute to a broader understanding of how communication and knowledge dissemination infrastructure can drive entrepreneurship and firm growth, carrying important implications for contemporary discussions on infrastructure development, its potential to stimulate entrepreneurial activity, innovation, and foster local economic communities. This paper was accepted by Olav Sorenson, organizations. Funding: The authors gratefully acknowledge funding from the Harvard Business School Division of Research and Faculty Development. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.03369 .