system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: How and why do some banks offer annual interest on the money in your savings account?
gpt
Banks make their money on loans and mortgages. In order to sell those, they need money to actually give out. They do this by incentivizing other people to save their money with them, so they can use some of it for loans. In return, the people whos money they use get a little cut of the profit from those loans in the form of interest on their savings account.