The Comma That Can Get You Sued

Most grammar debates are low stakes. Oxford comma or no Oxford comma tends to show up on lists of things writers argue about, right alongside whether to put one space or two after a period. It feels like a personal preference, the kind of thing a style guide settles and everyone moves on.

Then a dairy company in Maine lost a $5 million lawsuit over one, and the conversation changed.

What actually happened

In 2017, a group of truck drivers sued Oakhurst Dairy over unpaid overtime. Maine state law listed activities that did not qualify for overtime pay. The relevant line read:

The canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of perishable foods.

The drivers argued that "packing for shipment or distribution" referred to a single activity, meaning their distribution work was not covered by the exemption. The dairy argued that "packing for shipment" and "distribution" were two separate activities and both were exempt.

The court sided with the drivers. Without a comma after "shipment," it was impossible to tell whether "distribution" was its own item on the list or just part of the phrase "packing for shipment or distribution." That ambiguity cost the dairy $5 million.

One comma. An enormous difference.

Why the Oxford comma is not optional in professional writing

The Oxford comma is the comma placed before the final item in a list. "We offer editing, proofreading, and coaching" uses one. "We offer editing, proofreading and coaching" does not.

Style guides disagree on whether it is required. The Associated Press Stylebook traditionally discourages it in news writing. Chicago Manual of Style recommends it. Many writers treat it as a matter of taste.

But taste is not the issue. Clarity is.

When a sentence lists three or more items and the final two could be read as a single unit, the Oxford comma removes the ambiguity. It signals that everything after the last comma is a separate, standalone item. Without it, readers have to interpret the structure of the sentence instead of just reading it.

In casual conversation, that interpretation happens quickly and rarely causes problems. In a contract, a statute, a company policy, or a legal filing, that same ambiguity can mean two completely different things depending on who is reading it.

Other cases where this has mattered

The Oakhurst case is the most cited example, but it is not the only one.

A 2006 Canadian telecommunications dispute over a contract between Rogers Communications and Aliant turned on comma placement in a clause about termination rights. The misplaced comma changed who could cancel the agreement and when, resulting in a ruling that cost Rogers approximately $2 million.

Courts have a long history of resolving disputes rooted in punctuation because legal language is interpreted precisely. What reads as informal or stylistic in everyday writing becomes a source of binding meaning in formal documents.

What this means for your writing

You may not write legislation or contracts. But if you write anything that defines terms, outlines responsibilities, describes services, or sets expectations, ambiguity is a liability.

This applies to proposals, agreements, website copy, employee handbooks, and even marketing materials that make claims. The goal is not to sound legal. The goal is to write clearly enough that there is only one reasonable interpretation of what you mean.

The Oxford comma is the simplest possible insurance against one common type of ambiguity. It costs nothing to add. It has, in documented cases, saved millions.

The bottom line

Grammar rules exist because language requires shared interpretation. When punctuation is missing, readers fill in the gaps with their own understanding. Most of the time, that works out fine.

Occasionally, it goes to court.

Use the Oxford comma. Not because a style guide says so. Because clarity is not a stylistic preference — it is professional protection.