Back in the day, a loan shark was a criminal who charged an outrageous 20% interest for money. Working class folks were at the mercy of these "six-for-fivers."
Ronald Reagan became President and now established banks could charge 35% or more.
Yeah, a factory worker would get $5 and pay back $6 the next week. That was a terrible crime. Then Reagan deregulated the banks and it became business as usual.
I'd like to add that there are good versions of "microloans"! I learned that there used to be (or still are, didn't check) non-profit " banks" in some parts of India (and South africa I think) that would give out small loans of a few dollars to a few hundred dollars (which can be quite a lot of money in India). There was no collateral and low interest, but a group of people had to apply for a loan together. Until the first loan was paid back, the rest of the group couldn't apply again.
It was meant to provide financial backing and capital to microbusinesses (e.g. fishers, farmers, peddlers) that would otherwise be excluded from the financial market due to a lack of collateral and otherwise be forced to take high-interest loans.