Final answer:
A Systemically Important Financial Institution (SIFI) is informally referred to as Too Big to Fail. This status is given to financial institutions that are considered so large and interconnected that their failure could have a significant negative impact on the overall economy.
Step-by-step explanation:
A Systemically Important Financial Institution (SIFI) is an official status known more informally as Too Big to Fail. This term refers to financial institutions that are considered so large and interconnected that their failure could have a significant negative impact on the overall economy. These institutions are often subject to stricter regulations and oversight to mitigate the risks they pose to financial stability.