Why did the number of American corporations begin to increase in the 1830s

Because corporations encountered a more propitious legal system that allow them to grow. Corporations started to have rights that they didn't have before. For example: In Trustees of Darmouth College v. Woodward, this bill basically stated corporate charters inviolable. In Bank of the USA v. Deveaux, this bill allow Banks to sue. The 1830s was the decade in which the USA moved to the west and many entreprenurs made money and companies grew at a corporate level.

States began passing general incorporation laws.