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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!

Andrew
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  • Related: http://english.stackexchange.com/questions/112248/numeric-abbreviations-in-business-quotes –  Jul 02 '14 at 20:36
  • Although it's related, it doesn't really answer the question. It simply states that M stands for millions, which is not true in accounting/finance. There are people in this audience that will definitely know that M is the thousands symbol and MM is the millions symbol. I feel that using M as the millions symbol instead will leave some of them feeling that it is incorrect usage. – Andrew Jul 02 '14 at 20:39
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    *I* don't know that MM stands for "millions". In my universe, it's always just £1M for a million pounds. I wouldn't know what to make of £1MM. – FumbleFingers Jul 02 '14 at 20:44
  • @FumbleFingers, it appears to be American usage. – Andrew Jul 02 '14 at 20:50
  • In financial business I have never seen symbols mixed together ( K, M, B and T) but rather it is common to use them with numbers like: 3K, 2M or 4B. The use of numbers with symbols is very clear and avoids misunderstandings. –  Jul 02 '14 at 20:55
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    I've been revising presentations for US financial-services CFOs and other senior managers for twenty years, and they have all used M for million, not thousand; I've never seen MM. Of course my guys rarely stoop to mentioning any value less than a hundred thousand ($0.1M) or so ... – StoneyB on hiatus Jul 02 '14 at 21:09
  • @ Andrew: So just as the Mars Climate Orbiter apparently failed because Americans couldn't stick to a single system, are we therefore going to discover the global financial crisis was actually caused by American banks lending millions ($MM) to people who only paid back thousands ($M)? – FumbleFingers Jul 02 '14 at 21:09
  • @FumbleFingers I agree with you. In my accountancy career, much of it with multi-national companies, I always used £K for thousands and £M for millions. For column headings I would sometimes use £000s for thousands. I never recall any confusion. – WS2 Jul 02 '14 at 22:40
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    This would be a question of corporate jargon and not English, US or UK. – Oldcat Jul 02 '14 at 23:02
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    @WS2: I do have the vague sense that K and M aren't really part of the same set of abbreviations. I'm okay with K=Kilo, M=Mega, but it unravels slightly when I have to connect K=Kilo, M=Million. Partly for that very reason, I also used to sometimes use £000 on column headings. – FumbleFingers Jul 02 '14 at 23:19
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    For the purposes of clarity, you probably shouldn't mix SI prefixes with "business world accounting" symbols; Because there is overlap between these groups, there is a great possibility that confusion may result. I suggest you pick one convention of expression, and declare it near the beginning of any document. Incidentally, this doesn't really seem like an ELU question... – user867 Jul 03 '14 at 04:44
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    Don't mix symbols. Instead make a prefix that numbers are in "scope" for example; all numbers are in thousands - and then omit the number of zeros that the scope dictates. (Also by the way - I've never seen MM being used for millions either, neither in American financial books (micro/macro/accounting) nor European so it might be a specific 'flavor' more-so than a standard). – Allan S. Hansen Jul 03 '14 at 05:37

4 Answers4

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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.

user82900
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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.

joe m
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  • B for billion? I have usually seen G (as in giga, another SI prefix) and T (tera) for trillion. – StenSoft Jun 12 '15 at 15:01
  • Some also use xxxxMM or xMMM for billion (1000^3), since billion may mean million million in some areas. See https://www.youtube.com/watch?v=C-52AI_ojyQ – Greg Bray Jan 27 '16 at 16:48
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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.

Yaniv
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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.

Charlie
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Kid
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