I've found answers on the web but also got conflicting answers from financial professionals (coworkers).

In metric, you'd use M (mega) for million, G (giga) for billion and T (tera) for trillion. The only financial specific similar abbreviation I can find is MM for million (financial notation, according to wikipedia).

What's the AP style (or equivalent) abbreviation for billion and trillion in a financial context?

Bonus: where would I find this information?

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    I think this is a duplicate question. Will try to did the earlier version when I'm at my laptop and not using the mobile interface. Commented Feb 1, 2014 at 0:10
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    This is not an exact duplicate. Also, a financial news context is very different from a financial document context; reporting & news are pretty much by-definition for a broader audience than the materials & topics they cover. M for thousands and MM for millions would only ever be used in a context where the audience is proficient with financial jargon.
    – Patrick M
    Commented Aug 25, 2014 at 20:34
  • Why don't we use MY? It's less confusing than MM.
    – user98672
    Commented Nov 21, 2014 at 23:00
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    Generally, Roman numeral MM stands for 2000. Look (quickly) in movies produced this year for the date MMXIV. I have heard of M with a bar over it for (some larger amount).
    – GEdgar
    Commented Nov 22, 2014 at 0:10
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    The "MM" was borrowed from Roman Numerals, though it does not follow the same conventions. Romans rarely needed very large numbers, so they never developed a consistent notation. At various points and places 1,000,000 was either (M), M̅, or (MM). The latter was hijacked by the financial industry as a way to denote "million" while the term "milliard" was still around (still officially used in the UK until '74). Milliard got the M̅.
    – Chris S
    Commented Jul 1, 2015 at 19:08

5 Answers 5


I have seen million, billion, and trillion abbreviated as M, B, and T respectively. However, I would not bet that that is a standard abbreviation.

$3.1M settlement in Daniel McCormack priest sex abuse case for Chicago Archdiocese
Lawyers: $9M settlement for boy's cerebral palsy - Washington Times
JPMorgan reaches record $13B settlement with DOJ
Big win for BofA: Judge OKs $8.5B settlement with mortgage bondholders
China Now Owns a Record $1.317T of U.S. Government Debt

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    Right but I'm sure I've seen MM used for million in finance. It's kinda old-school so I was wondering if there were other old school abbreviations for billion etc. en.wikipedia.org/wiki/MM
    – jcollum
    Commented Jan 31, 2014 at 22:31

It certainly depends on your audience. I generally use $___MM, which was, and still is, often used by accountants and economists. Before "K" was adopted as the colloquial way of writing a thousand (i.e. $35k to mean $35,000), it was common to use "M" instead; "M" being the Roman Numeral for 1,000. As a result, "M" simply became shorthand for adding three zeros and thus "MM" became the shorthand for adding six zeros.

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    This is a very interesting etymology. Do you have any citation for this? Commented Apr 10, 2017 at 15:01

UK media tend to use m and bn for million and billion: "Grenier rejects £10m Newcastle switch", "Liberty Global buys Ziggo for €10bn". However, this usage is much less common in the US.

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    Ugh, that's awful, using m for million in a country where mL is a milliLiter (i.e. 1 / 1000 of a liter)
    – jcollum
    Commented Jan 31, 2014 at 22:32
  • @jcollum These conventions are also claimed to be in use in the US (see abbreviations.com). Commented Jan 31, 2014 at 23:42
  • @EdwinAshworth likewise for MM: abbreviations.com/serp.php?st=MM&o=2
    – jcollum
    Commented Feb 1, 2014 at 3:02
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    @jcollum - but m cannot lead to any confusion, because it is preceded with a number with a currency sign. Commented Jun 16, 2016 at 20:00
  • Just one sample of anecdotal evidence, market analysis reports from Frost and Sullivan use Mn for million and B for billion. Otherwise it seems common to use Bn for billion.
    – dioid
    Commented Aug 11, 2020 at 11:10

I have worked in equity markets for 20 years and poor abbreviations drive me crazy. Regretfully, until the USA goes metric there's going to continue to be problem with this.

Metric, engineering standards are useful:

CORRECT m = metre mm = millimetre

k = kilo (10^3, thousand) M = Mega (10^6, million) G = Giga (10^9, billion) T = Tera (10^12, trillion) P = Peta (10^15, quadrillion) E = Exa (10^15, ??)

In keeping with this I use: M = million B = billion T = trillion

etc...but it's not clear.

INCORRECT mm = very common. In many measures of materials..."million metric tonnes (tons)" is abbreviated to mmt. From that I see many analysts use mm to mean million. But it is a terrible abbreviation. I look forward to paying someone, some day, say $1mm. In response, I would cut 1 millimetre off a $1 bill and hand it to them... ;-)

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    It's a relevant comment but not really an answer to the question.
    – jcollum
    Commented Nov 8, 2014 at 19:33

Sadly, dollars are not a metric base unit, so the use of metric prefixes would be entirely ad-hoc on your part. The usual way is to put the units on the axis of a graph or legend on a table, or early in a text description and leave it at that.

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