This post is one in a series on prominent company nicknames. See all 25, and share your thoughts and memories about Fannie Mae and Freddie Mac below in the comments.

How did Federal National Mortgage Association and Federal Home Loan Mortgage Corp. (FHLMC) get their nicknames -- Fannie Mae (NYSE: FNM) and Freddie Mac (NYSE: FRE)?

According to Fannie Mae's website, its formal name is no longer Federal National Mortgage Association. It appears that the nickname took over the formal name. The reason? To "eliminate confusion among investors and consumers alike regarding various names in use for Fannie Mae." As a result, on January 6, 1997, Fannie Mae's stock started being listed under the name Fannie Mae rather than Federal National Mortgage Association.

Slate gets the award for offering an explanation of the source of the nicknames. I cannot improve on its explanation, which is as follows: "FNMA got its moniker because of its acronym; when you try to pronounce it as a word, it comes out sounding something like 'Fannie Mae.' When it came time to nickname the competitor, however, FHLMC didn't naturally sound like a recognizable name. 'Freddie,' then, is a take on 'federal,' and 'Mac a reference to the terminal 'MC.'"

Peter Cohan is President of Peter S. Cohan & Associates. He also teaches management at Babson College and edits The Cohan Letter. He has no financial interest in the securities mentioned.