The Question and Answer Board

[SPM555]

As a young banker in the mid- 80’s I learned what had been taught for many decades before, that we abbreviate thousands in our analysis with a letter M. If we wanted to denote millions, we would show that as MM. For this, we should credit the Romans. M is the Roman numeral for thousand and MM is meant to convey one thousand thousand – or Million. To take it further; one billion would be shown as $1MMM or one thousand million. However, truth be known, if there were an ancient Roman here and we asked him to interpret our use of roman numerals, we would find that technically MM means two Thousand and MMM means three thousand, so there are flaws in this tradition. This reminds me of the old joke about an ancient Roman that goes into a bar holds up two fingers in a peace sign to the bartender and says “Five beers, please”.

https://www.orsurety.com/blog/is-it-m-for-thousand-and-mm-for-million-or-k-for-thousand-and-m-for-million-im-asking-for-a-friend