One of the most consequential yet unexamined developments in finance is the recent evolution of large financial technology platforms. In the first analysis of its kind, we scrutinize the world’s $89 trillion investment and asset management industry to explore the function of these systems, to consider their possible risks, and to develop a taxonomy for their regulation. This analysis is essential because these systems now play a critical role in asset management, rendering nugatory several layers of existing regulation. While the COVID-19 pandemic has caused havoc with economic activity, it has accelerated this process of digitization and concentration of financial control. The leading example of such a platform is BlackRock’s Aladdin, a system used to manage the risks relating to ten percent of the world’s investment assets and which institutional investors – as well as the U.S. government – admit they cannot operate without. Even greater concentrations of financial power are possible when Big Technology firms and finance unite. Ant Group, a spinoff of Alibaba, controls a financial ecosystem for over 1.2 billion clients – twenty-one percent of the world’s adults – covering all financial services, including payments, insurance, asset management, and deposits. Large U.S. financial and tech firms, including Facebook, Apple, and Google, are working hard to emulate Ant’s scale and scope, driving concentration into a small number of dominant digital finance platforms. Although Financial Technology is typically associated with small innovative firms, we argue that these giant digital finance platforms are already having a far greater impact on society. We identify the economic reasons for the dramatic ascendancy of these financial leviathans and propose a legal framework for mitigating their threats to national security, financial stability, consumer protection, antitrust and cybersecurity.