[nostromo]

M is often used to mean 1,000 from the Roman Numeral, so using it to mean "one million" is confusing.

It's not just finance, but in other contexts too, such as online marketing CPM = Cost Per Thousand.

MM then is used to denote a thousand thousands, or one million. In online marketing sometimes you'll see CPMM = Cost Per Million.

[sebastianavina]

k is used for 1000, M for millions... damn americans.

[yen223]

Unless you're talking about kilobytes, in which case k = 1024.

Unless you're a strict follower of the IEC standard, in which case k = 1000, and what I was talking about was a kibibyte.

Standards are hard. It's not just the Americans' fault

[killface]

blame the brits, not the americans.

[psykovsky]

Can we just blame one person instead of an entire country?

[nkozyra]

Blame Todd. Todd did this to us.

[allard]

Blame the accountants. We're engineers et al. We use SI.

[jeroen]

K, not k.

[tempestn]

Actually, he's right; the abbreviation for kilo (thousand) is lower-case k. The abbreviation for mega (million) is upper case M. (Lower case m is milli (thousandth).)

[JoshTriplett]

When, whether talking about money or not, have you ever seen someone write 100M to mean "a hundred thousand"? That would be completely ridiculous. Roman numerals are not used for that.

[nostromo]

It's used exactly like that in finance all the time.

http://www.accountingcoach.com/blog/what-does-m-and-mm-stand...

http://english.stackexchange.com/a/182072

[bjterry]

That guy's response makes no sense to me. I worked in finance and banking for five years and didn't even once see M used to represent thousand. Perhaps times have changed and that used to be common. k (thousand) and M, m or MM (millions) were used though.