Mixing use of K for thousands and MM for millions

Question

Traditionally, M is used as the symbol for thousands and MM for millions in the business world, particularly in accounting. However, there has been a growing tendency to use K as the symbol for thousands instead of M.

Would it be considered acceptable to use K for thousands and MM for millions, effectively mixing symbols?

For example, in a document that requires the use of symbols because of limited space in a table, I see "500K-1MM" to stand for "500,000-1,000,000". This document is written for a general professional audience.

My thoughts are:

If K and MM are used, it's bad style because the symbols are being mixed up. But if M and MM are used, non-experts might not even be aware that M is a symbol for thousands and get confused. It seems like that the safest choice to ensure comprehension is to use K and MM, but something about mixing the symbols just doesn't seem right to me.

Thanks!

Answer 1

I worked in banking for 27 years (Federal Reserve Bank of Atlanta and Bank of America), and my experience in financial services was that M and MM were consistently used for thousands and millions, respectively. This practice was across the board - exam reports, internal reporting, and so on. They never used K for thousands.

It would be bad form to mix K and MM because they are two different systems of notation. The best path would be to determine what your audience is most likely to understand. M and MM are roman numerals where M is one thousand and MM is intended to denote "one thousand thousands." K comes from kilo which is the unit prefix in metric systems to indicate "times one thousand." The corresponding prefix for million is M.

So you should use either K and M or M and MM, but do not mix the two.

Answer 2

In the general environment of municipal government, for dollars we use K for thousands, M for millions and B for billions.

However, I often see where those who are dealing with financing (banks and investment houses for bonds) use the MM for millions of dollars.

That being said, I think the most appropriate usage is using one alpha symbol consistently so that would lead to using K, M and B.

Answer 3

I have had the same dilemma and come to the conclusion that using k for thousands and MM for millions is a reasonable and pragmatic thing to do.

The problem with M is that depending on the audience it can mean either thousands or millions. This is ambiguous; hence, if you wish to be unambiguous the use of M to mean either thousands or millions is to be avoided. Thus, we're left with k and MM as to unambiguous ways to denote thousands and millions respectively.

Answer 4

As one discovers from the many variant opinions this topic generates significant misunderstanding. By placing the first occurrence of a given symbol (abbreviation) in each article or presentation within parentheses you remove all doubt about what you mean.

For example: "First quarter earnings were up by $2 million (MM), a significant improvement over the the $250 thousand (M) loss in the final quarter of last year.

Then you may use the abbreviations throughout your article without concern for being misunderstood.