More Syntactic Ambiguity: The Serial Comma

This item at The Volokh Conspiracy noted that the “serial comma” has been appearing less and less frequently in the New York Times. At Legal Blog Watch, Eric Lipman pointed out that a Volokh commenter had suggested that the serial comma is important for clarity in contracts. Here’s the entire comment, posted by “Mark”:

I think we should at least all agree that the serial comma is an absolute must in contracts. It doesn’t break up the flow of a series to add the comma–you read it in anyway–but it does provide clarity, which as I understand it is what contracts are all about.

On reading the comment, I realized—shock horror probe!—that I had never explored how the ambiguity that can arise when you drop the serial comma might manifest itself in a contract. It’s another example of syntactic ambiguity, which is caused by uncertainty over which part of a sentence a given word or phrase modifies. (If you want other examples of syntactic ambiguity, search for “syntactic” on this site.)


The serial comma is the comma used immediately before the and or or preceding the final item in a list of three or more items. You can either include the serial comma (I like apples, cherries, and grapes) or omit it (I like apples, cherries and grapes). At the moment I don’t have access to my usual authorities on usage, but this Wikipedia entry gives a decent account of the arguments for and against the serial comma and which position the various style guides take.

Using the serial comma can resolve ambiguity. Wikipedia provides the following example, a “possibly apocryphal book dedication”:

To my parents, Ayn Rand and God.

Readers could derive two possible meanings from this. The first is that the book is dedicated three ways. The second that the book is dedicated to the writer’s parents, who happen to be Ayn Rand and God. As Wikipedia notes, “Ayn Rand and God can be read as in apposition to my parents, leading the reader to believe that the writer’s parents are Ayn Rand and God.” That meaning is obviously ludicrous, but change the components and real confusion could be the result.

Inserting a comma before and eliminates the ambiguity:

To my parents, Ayn Rand, and God.

But the serial comma can also create ambiguity. Consider the following adjusted, serial-comma-containing version of the dedication:

To my mother, Ayn Rand, and God.

Readers could derive two possible meanings from this. The first is that the book is dedicated three ways. The second that the book is dedicated to the writer’s mother, who happens to be Ayn Rand, and to God.

Omitting the serial comma eliminates the ambiguity:

To my mother, Ayn Rand and God.

An Example from a Contract

Some rooting around online led me to Telenor Mobile Communs. v. Storm LLC, 587 F. Supp. 2d 594, 605–08 (S.D.N.Y. 2008). (Go here for a PDF copy.) At issue was whether someone was an affiliate of a particular entity, and that brought into play the following definition of “control” contained in a shareholders agreement:

[C]ontrol (including, with its correlative meanings, ‘controlled by’ and ‘under common control with’) shall mean, with respect to any Person, the possession, directly or indirectly, of power to direct or cause the direction of management or policies (whether through ownership of securities or partnership or other ownership interests, by contract or otherwise) of a Person.

Here’s what the court had to say about the alternative meanings made possible by the lack of a serial comma before “or otherwise”:

Contrary to the Altimo Entities’ argument, the Agreement’s definition of control contemplates control exercised through  means other than ownership interests. The definition of control states that the “power to direct” may arise from “ownership of securities or partnership or other ownership interests, by contract or otherwise.” The phrase could be read, as the Altimo Entities assert, as limited to powers arising out of ownership interests. In this reading, “by contract or otherwise,” specifies the source of the ownership rights, and “otherwise” refers to sources of ownership rights other than contract. However, the phrase could also be read, as Telenor suggests, as a list of the sources of the “power to direct.” That is, the power to direct may arise either through “ownership of securities or partnerships or other ownership interests,” through “contract,” or “otherwise.” In this reading, the “power to direct” is not limited to powers arising out of ownership interests. Instead, such powers may also arise through “contract” or “otherwise.”

Telenor’s interpretation is the more reasonable one. First, the Altimo Entities’ proposed interpretation gives “by contract or otherwise” an awkward and cramped meaning. The specification of the ownership interests as being “ownership of securities or partnerships or other ownership interests” is clear on its own. The addition of the phrase “by contract or otherwise” adds little, if any, clarity to the scope of the ownership interests. It also suggests that ownership interests normally arise out of contract, but in fact they more often arise out of ownership of shares, or out of a partnership, than out of contract. Moreover, aside from property, partnership, and contract, it is not obvious how ownership interests might “otherwise” arise. Read as the Altimo Entities would have it, the phrase is either redundant or obfuscating, adding nothing but confusion to the definition.

Second, Telenor’s interpretation more reasonably defines “control.” Ownership is not the only way in which one person or entity may control another. Contractual arrangements, such as shareholder agreements, employment contracts, or agency or other commercial contracts, can allow one entity to wield significant power over another. It would not be consistent with the purposes of the non-competition provision for the parties to prohibit Alfa Group from directly or indirectly owning shares of a competing telecommunications venture, but to control one through another person or entity that was, for some reason other than ownership, its puppet.

This conclusion is fortified by the fact that the contractual provision appears to be modeled on other legal documents that define “control” broadly, for similar purposes. Thus, Telenor’s interpretation squares with the interpretation of the almost  identical definition of “control” used by the SEC in defining the scope of “control person” liability under the Securities Exchange Act of 1934, 15 U.S.C. § 78t(a).

To its discussion of the difference between the shareholders agreement’s definition and the SEC’s definition, the court added the following footnote:

One other difference, which is perhaps illuminating, is that the Shareholders Agreement drops the comma after “by contract” and before “or otherwise.” The use of a comma before a conjunction joining the last two items in a list—the so-called “serial” or “Oxford” comma—is not universal, though it is “strongly recommend[ed]” by at least one authority, “since it prevents ambiguity.” The Chicago Manual of Style (University of Chicago Press, 15th ed. 2003). Indeed, the omission of the serial comma in the Shareholders Agreement definition of “control” accounts for much, if not all, of the confusion here. Had the Agreement incorporated the serial comma—i.e., control is power to direct “through ownership of securities or partnership or other ownership interests, by contract, or otherwise”—it would have been substantially clearer that non-ownership types of control are contemplated. The Shareholders Agreement omits the serial comma elsewhere, for example, in the text of the non-competition provision, see Section 6.02. This pattern of omitting the serial comma, together with the overwhelming consistency between the Agreement’s definition and the SEC’s definition, suggests that the omission of the comma was either inadvertent or a stylistic choice not intended to affect the meaning of “control” under the Agreement.


I think the Telenor court’s analysis makes sense. But as always, the question for the contract drafter is not how to make sense of a dispute but how to avoid dispute in the first place.

The simplest approach would be always to use the serial comma in a simple list of three or more items. It’s very unlikely that you’d find yourself in a situation where a serial comma creates ambiguity rather than resolves it.

And if you’re inclined to use what Wikipedia refers to as apposition, you certainly shouldn’t rely on omitting or including the serial comma to accomplish that meaning. Instead, restructure the provision. For example, instead of the fourth example above, you could say To God and to Ayn Rand, who is my mother. The language at issue in Telenor could have been restructured to match the SEC definition, or maybe including could have been used instead of or otherwise.

But more generally, you might want to limit your use of apposition, which I refer to as “needless elaboration.” (See MSCD 16.24.) It occurs when a contract provision refers not only to a given set but also to elements that compose all or part of that set, even though there’s no question as to the boundaries of the set. Needless elaboration is when you say “fish, whether fresh-water or salt-water,” rather than just “fish.” Similarly, for purposes of a contract it would be redundant to refer to your parents and then identify them as Ayn Rand and God.

Not all such elaboration is needless. It would, for example, be hard to eliminate it entirely from the language at issue in the Telenor case. But if you eliminate needless elaboration and are aware of, and scrutinize the wording of, any remaining instances of apposition, that would help you reduce the odds of confusion down the road.

But I wouldn’t want to overstate the significance of this kind of ambiguity. It seems to occur relatively rarely in contracts.

About the author

Ken Adams is the leading authority on how to say clearly whatever you want to say in a contract. He’s author of A Manual of Style for Contract Drafting, and he offers online and in-person training around the world. He’s also chief content officer of LegalSifter, Inc., a company that combines artificial intelligence and expertise to assist with review of contracts.

11 thoughts on “More Syntactic Ambiguity: The Serial Comma”

  1. One way to avoid these problems is to habitually use letters and numbers to make clear the members of the series. So, "To (1) my parents, (2) Ayn Rand and (3) God" can be distinguished from "To my parents, (1) Ayn Rand and (2) God." Another advantage to doing this is that when you find yourself using romanette (i), (ii), and (iii) in a sentence, as you would need to in the Telenor example, it serves as a signal that perhaps you should redraft the sentence. (Sorry, couldn't resist using "romanette" in a comment since I also had never heard of it before

    • Kazu: Yes, enumeration can be used to avoid syntactic ambiguity, as I note in MSCD. But I'm not keen on your second reworked example. And romatte is cumbersome, so it goes at the bottom of my enumeration hierarchy; see MSCD 3.29. Ken

  2. Ken

    Could it not also be clarifying to drop the "and" altogether, as in: "I like: apples, cherries, grapes." One might interpret the lack of the serial comma before the "and" as meaning the author likes "cherries and grapes" but only in together, as in fruit salad, versus separately.

    One might provide further clarity by formatting the series as a table. E.g.:

    I like to eat:
    cherries and grapes
    bananas and strawberries

    I dedicate my book to:
    My parents
    Ayn Rand

    Numbering may aid clarity, but the numbers and parenthesis can also contribute to visual clutter. Numbering the above lists does not add much in clarity, but using vertical lists does contribute to page length.

    BTW, U.S. lawyers have used "romanette" at least since the early '80s to mean a small roman numeral.

  3. Ken, I would like to suggest that your example of the dedication when your mother is in fact Ayn Rand is misplaced (if I can put it that way). That is not an example of the serial comma but of commas being used to clarify the identity of the preceding phrase.

    So for example, if I say, "I dedicate this book to my brother, Richard," the implication is tha tI have but one brother. If I have two brothers, however, and (damn the consequences), I'm only dedicating my book to one of them, then I couldn't simply say, "I dedicate this book to my brother," since it would be necessary to clarify which one. I would then say, "I dedicate this book to my brother Richard," to clarify to those who know the family that I am deliberately omitting my brother Peter. (Fortunately, I have never written a book and I have no brothers, so I have never had to deal with the situation!)

    This is the way that my wife, the copy editor, has explained it to me.

    • John: In my third example, the comma in question might be a serial comma, but it also might not. So I think I'm OK.

      By the way, I'm beginning to regret the overwrought dedication example! I've never even read any Ayn Rand!


      • I've never read her either, but am I the only one who found your example all the more amusing in that Ayn Rand had no use for religion, and disdained all who did?

        • I was vaguely aware that Any Rand can be placed at the other end of the spectrum from conventional deities, while at the same time she perhaps attracts a deity-like level of devotion from followers such as Alan Greenspan.

  4. Interesting discussion! Several, distinct points seem to emerge:

    1. There is the purely stylistic question of whether to use a serial comma in lists. I had understood that this practice was more commonly seen in the US than in the UK, but now I am beginning to doubt whether it is that simple. At school (UK), I was taught not to include the comma, but in recent years I have started to do so. I had always heard it described as the Oxford comma, but that may be something to do with where I live and work (!)

    2. As in the Telenor example, long, complex phrases can be ambiguous or at least unclear. I agree with Ken's comments about the need for restructuring, and (if you feel the need for something this "thorough") possibly using a statutory or other official definition – see for example s.416, (UK) Income and Corporation Taxes Act 1988. Interestingly, the court in Telenor didn't seem to regard the presence or absence of a comma as conclusive.

    3. We shouldn't confuse lists with subordinate phrases (is that the right expression?). "To my mother, Ayn Rand, and God" might be a list or it might be a shorthand way of saying "To my mother, whose name is Ayn Rand, and God. If it is a list, then in a contract there are several ways of removing the uncertainty, eg putting in numbers, as a previous blogger has suggested, or changing the order of words. I probably wouldn't try to fix it by putting in or taking out a comma, though.


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