The source of "cum-ex"?

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"It May Be the Biggest Tax Heist Ever. And Europe Wants Justice." NYT 1/23/2020:

Martin Shields and Paul Mora met in 2004, at the London office of Merrill Lynch. […]

Today, the men stand accused of participating in what Le Monde has called “the robbery of the century,” and what one academic declared “the biggest tax theft in the history of Europe.” From 2006 to 2011, these two and hundreds of bankers, lawyers and investors made off with a staggering $60 billion, all of it siphoned from the state coffers of European countries.

The scheme was built around “cum-ex trading” (from the Latin for “with-without”): a monetary maneuver to avoid double taxation of investment profits that plays out like high finance’s answer to a David Copperfield stage illusion. Through careful timing, and the coordination of a dozen different transactions, cum-ex trades produced two refunds for dividend tax paid on one basket of stocks.

One basket of stocks. Abracadabra. Two refunds.

You can learn more about this from the source at But since this is Language Log rather than Evil Bankers Log, I'm going to focus on the claim that "cum-ex" is from the Latin for "with-without".

Because it isn't, really — and therefore I'm asking LLOG readers to help me figure out where the phrase cum-ex actually comes from. It's true that cum means "with" in Latin. But according to Lewis &  Short, ex basically "denotes out from the interior of a thing".

As often with basic spatio-temporal terms, ex can have spatial meanings ("In a downward direction, from, down from, from off", or "In an upward direction, from, above"); temporal meanings ("From a certain point of time, ie. immediately after, directly after", or "From and after a given time, from … onward"); and a bunch of extended meanings, "In other relations, and in gen. where a going out or forth, a coming or springing out of any thing is conceivable", such as "To indicate the material of which any thing is made or consists of", or "To indicate the cause of reason of any thing, from, through, by, by reason of, on account of", or "To indicate a transition, i.e. a change, alteration, from one state or condition to another", or "To designate the measure or rule, according to, after, in conformity with which any thing is done".

The Latin for "without" would be sine — but the scam was called "cum-ex", not "cum-sine".

No doubt "cum" and "ex" come from some fragments of legal Latin involved in the origins of the scam. But I'm drawing a blank about what the fragments were. And Wikipedia's List of Latin Legal Terms doesn't help me — here are all the entries containing either cum or ex:

compensatio lucri cum damno
cum beneficio inventarii
cum onere

ex aequo et bono
ex ante
ex cathedra
ex concessis
ex delicto
ex demissione
ex facie
ex fida bona
ex gratia
ex officio
ex parte
ex post
ex post facto
ex proprio motu
ex rei
ex tunc
ex nunc
ex proprio motu
ex propriis sensibus
mora solvendi ex re
mora solvendi ex personae
ex intervalo temporis

The last one is suggestive — it's given in the definition of uno contextu as

Contemporaneously; when the phases of something are done without interruption or any intervening action; specifically, executed in one single execution ceremony (vs. ex intervalo temporis)

But then where's the cum?




  1. caneron said,

    January 24, 2020 @ 7:53 pm

    Did they mean "without" in the sense of towards the outside, or simply outside, of a building, house, or room?

    "Our carraige awaits without."

    "There is a knocking without."

  2. DaveK said,

    January 24, 2020 @ 7:55 pm

    My guess is that the “ex” is short for some English word like exclusion or explanation, so the whole phrase would mean some bit of legal or accounting jargon like “with exclusions” or whatever.

  3. rbl said,

    January 24, 2020 @ 8:01 pm

    The terms in play seem to be "cum dividend" and "ex-dividend". "Ex-dividend describes a stock that is trading without the value of the next dividend payment. The ex-dividend date or 'ex-date' is the day the stock starts trading without [!] the value of its next dividend payment."

  4. J.W. Brewer said,

    January 24, 2020 @ 8:41 pm

    Almost certainly from the venerable "ex dividend" usage, which then spread more recently among financiers of limited Latinity to mean "without" more generally, such that once you're immersed in the relevant jargon e.g. "Asia ex Japan" transparently refers to a portfolio of securities from issuers in all relevant Asian markets except Japan. You can hardly expect "sine Iaponia" these days. Alas and alack.

  5. J.W. Brewer said,

    January 24, 2020 @ 8:49 pm

    and by "venerable" I mean, for example, that google books can easily find you an 1807 usage of "ex dividend" (referring in context to "Navigable Canal Shares," which I take it were the hot new investment back then) in essentially the same sense that a 21st century trader would understand it.

  6. Andrew Usher said,

    January 25, 2020 @ 8:23 am

    No one has mentioned, if 'ex' does not mean 'without', how 'ex-dividend' might have come about. 'Outside of' the dividend period?

    [(myl) It seems to be the "after in time" reading. According to investopedia:

    The ex-dividend date or "ex-date" is the day the stock starts trading without the value of its next dividend payment. Typically, the ex-dividend date for a stock is one business day before the record date, meaning that an investor who buys the stock on its ex-dividend date or later will not be eligible to receive the declared dividend. Rather, the dividend payment is made to whoever owned the stock the day before the ex-dividend date.


    I understand, and may have used myself, the 'Asia ex Japan' sense – which sounds like a shortening of 'except' or 'excluding' which would be normal words to use there. If it is it would surely first appear in writing.

    [(myl) This one is plausibly another extension of the core "out from the interior of a thing" meaning, so that "ex Japan" would mean "outside of Japan", not so much in the strict geographic sense as in the mode of Groucho Marx's joke "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read." ]

    k_over_hbarc at

  7. David Marjanović said,

    January 25, 2020 @ 8:32 am

    This has been in the German media for months.

    Wikipedia explains it all: "Dividend stripping is the practice of buying shares a short period before a dividend is declared, called cum-dividend, and then selling them when they go ex-dividend, when the previous owner is entitled to the dividend."

    …where "ex-dividend" is a link to the article on the ex-dividend date, which begins as follows: "The ex-dividend date, also known as the reinvestment date, is an investment term involving the timing of payment of dividends on stocks of corporations, income trusts, and other financial holdings, both publicly and privately held. The ex-date or ex-dividend date represents the date on or after which a security is traded without a previously declared dividend or distribution.[1] Usually, but not necessarily, the opening price is the last closing price less the dividend amount.[2]"

    I found this by googling for cum-ex. The knowledge of the world is at your fingertips.

  8. David Marjanović said,

    January 25, 2020 @ 8:34 am

    …and the German Wikipedia article specifies that cum refers to Wertpapiere mit Dividendenausschüttungsanspruch, which I'd tentatively render as "shares that convey a right to receive dividends".

    None of this makes a lot of linguistic sense, but bankers tend not to be classicists…

  9. Andrew Usher said,

    January 25, 2020 @ 10:45 am

    I know what 'ex-dividend' means (in fact I read that investopedia piece just before posting), I was asking for any clues to its origin. If I didn't know the term, I would be likely to use 'without dividend' as the short form, which leads to the problem.

    [(myl) Connection to the original Latin usage is pretty clear — from the cited Lewis and Short entry,

    From a certain point of time, i. e. immediately after, directly after, after […] “statim e somno lavantur”

    "Statim e somno lavantur" word-for-word means "immediately after sleep they_wash". "Ex dividend" seems to be basically the same as "e somno" here.

    The immediate part isn't needed, either, as exemplified by some of their other citations, like “ex ea die ad hanc diem,” = "from that day to this day".]

  10. Rose Eneri said,

    January 25, 2020 @ 1:46 pm

    Might it be that the term ex-dividend came from the idea that one is buying the stock after the date the dividend would have been paid out to the seller, like "dividend out already." (Even if the actual dividend might not have been paid, it is still due to the seller, not the buyer.)'s 4th gloss of ex- is "Denoting removal or release.‘excommunicate’

    So, the dividend has already been released.

  11. .mau. said,

    January 26, 2020 @ 11:58 am

    AFAIK, Latin 'ex' also means "outside". Think of exclaves, for example, or excommunication (put someone outside the Christian community)

  12. Heino said,

    January 28, 2020 @ 12:57 am

    Since the participants continued to gain for some years, the expression must be shorthand for CUMulative EXploitation.

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