Nellie Mae
  
Learning about Nellie Mae is a little like learning about a Game of Thrones character. To understand it, you have to go through a little genealogy. Like...how Cersei Lannister is at least partially defined by the fact that her father is Tywin Lannister and her husband is Robert Baratheon and her brother is Jaime Lannister and her kids are...well, you get the point. Just how all that stuff matters to Cersei, getting to know Nellie Mae involves some familiarity with the Mae/Mac family line.
To start, Fannie Mae and Freddie Mac are the most famous members of the family. They are each what's called a GSE, or government-sponsored enterprise. That means they were set up by Congress and get some government backing, though they largely operate as separate private-sector companies.
Freddie and Fannie provide home loans, which makes them a central part of one of the most prominent parts of the U.S. economy. (Anyone who has ever dipped into the home market has at least a passing familiarity with Fannie and Freddie). Meanwhile, they got kind of infamous during the mortgage crisis of the mid-to-late 2000s.
Well, Fannie and Freddie have a cousin, Sallie Mae. It provides similar functions, only in the education space. It started as a GSE offering government-sponsored educational loans, but now provides private student loans as well, as well as other financial products.
Sallie has a little sibling...Nellie. Nellie Mae previously operated as the New England Loan Marketing Association, offering student grants in the New England area. It also provided student loans during its early life. Now its a subsidiary of Sallie Mae and exists as a non-profit organization, handing out education grants.