In 1986 the dominant form of the Fortune 500 industrial corporation changed from the multidivisional form (MDF) to the multisubsidiary form (MSF) (Zey and Camp 1996). We examine two major organizational perspectives (historical managerialism and agency theory) and an alternative perspective, the political economy contingency theory of capital accumulation (PECTA), to explain the transformation of Fortune 500 corporate form from MDF to MSF. Using event history analysis, we analyze data from 1981–1995 to define the covariates of this change, thereby predicting the risk of change to the now dominant MSF. The historical managerialism model considers assets as an indicator of size, operating profit margin as an indicator of efficiency, and return on sales as an indicator of profitability. The two major variables of the agency theory model are cash flow and debt-to-equity ratio. The alternative PECTA model considers tax savings resulting from changes brought about by the Tax Reform Act of 1986, percentage of shares held by institutional investors, shareholder return on equity, production-to-administrative intensity, dollar amount of acquisitions, and dollar amount of divestitures. Controlling for the natural log of gross assets, which has the strongest relationship to risk of transformation in dominant form from MDF to MSF, we found that the percentage of shares held by institutional investors, the sum of tax-free transactions (spin-offs, split-offs, and stock swaps), the total merger and acquisition activity, and the two-year lagged difference in the rate of first-level subsidiarization all had significant effects on the transformation of corporate form from the MDF to the now dominant MSF.