The growth of corporations during the Gilded Age was primarily driven by the growth of the manufacturing industry. This period saw significant industrialization, with advancements in technology and production techniques leading to the establishment of large-scale manufacturing operations. The need for capital to invest in machinery, infrastructure, and labor contributed to the rise of corporations, as they could pool resources and minimize individual risk.
While the growth of the finance industry also played a role in supporting corporations through investment and capital lending, and the agricultural industry experienced changes during this time, it was the manufacturing sector that fundamentally transformed the economy and led to the proliferation of corporations.