Oligarchy of wealthy is termed as:

A plutocracy is a system where the wealthy elite hold significant political power, often influencing governance through wealth. Studying plutocracy highlights the role of economic inequality in politics, the challenges of ensuring democratic fairness, and its impact on policy-making. It also offers insights into how wealth shapes governance structures, providing lessons on the need for transparency, accountability, and equitable policies to prevent undue influence and maintain democratic integrity in societies with concentrated wealth.