What does it mean when a bank is FDIC insured?

-it has insurance on the building
-it has insurance on its investments
-it guarantees that you won't lose all of your money
-it is one of the top 100 banks in the world

The correct answer is: it guarantees that you won't lose all of your money.

When a bank is FDIC insured, it means that it is a member of the Federal Deposit Insurance Corporation (FDIC), an independent agency of the United States government. The FDIC provides deposit insurance to customers of member banks, which ensures that if the bank fails, each depositor's funds, up to the insured limit, will be protected and guaranteed by the FDIC. This insurance applies to deposits such as checking accounts, savings accounts, certificates of deposit, and money market accounts. It does not necessarily mean that the bank is one of the top 100 banks in the world, nor does it imply insurance on the bank's building or investments.