The Mailbox Rule and How it Applies to Email

The Mailbox Rule (also occasionally referred to as the ‘posting rule’) relates to when something is legally deemed to have been posted, which in turn relates to, primarily, when an offer has legally been accepted in contract law. Of course, we say “post” because up until relatively recently, you put the thing in an actual post box, or mailbox. For purposes of email, an email is ‘posted’ when the email has been sent to its intended recipient.

Note that I said “sent”, not “received”.

Before we go any further, it helps to understand the basics of contract law, specifically the formation of a contract, as this is in large part where the Mailbox Rule has its roots.

The Basics of Contract Law

Very broadly speaking, the key elements that must be present to create a binding, legal contract are:

1. An offer of something
2. The other party’s acceptance of that offer
3. An exchange of value, meaning each party gets something of value out of the deal – this is known as ‘consideration’.

There also has to be an intention to create a legally binding relationship.

Now, of course, as nothing in the law is simple (otherwise I wouldn’t need to explain the law, and all we lawyers would be out of a job), there is a great deal more that goes into forming, and especially proving, a contract. But for the purposes of this article, these are the basics.

What Is the Mailbox Rule?

The Mailbox Rule as first conceived primarily, and most specifically, spoke to item #2 – acceptance of the offer.

The basic concept, first established by case law in the early 1800s, is that the acceptance of an offer is effective when the accepting party posts their acceptance in the mailbox, not when the offerer receives that acceptance. This allows the person accepting the offer to rely on the contract, as at that moment both parties have the intention for there to be a contract. It stops the offerer from deciding that they don’t want to do it after all, while the acceptor is already relying on the contract that they have accepted.

Over time, the Mailbox Rule has been applied to all sorts of scenarios in which Party A sent something to Party B, relying on the near-certainty that the very act of mailing that something to Party B meant that Party B would actually receive it. Of course, we know from the many, many court decisions dealing with (and indeed affirming) the Mailbox Rule that in fact sometimes Party B doesn’t receive whatever Party A sent.

So the Mailbox Rule is, for the most part, what we in the biz call a ‘rebuttable presumption’, meaning that we presume that whatever Party A sent was in fact received by Party B, but Party B has the opportunity, in court, to offer evidence to prove that they never actually received what Party A had sent them (or claims to have sent them).

So How Does the Mailbox Rule Apply to Email?

Of course, the Mailbox Rule, promulgated in the 1800s, could not possibly have anticipated the advent of email. And, as you may imagine, there have been a number of cases dealing specifically with the Mailbox Rule and email, and as you further may imagine, they don’t all agree with each other. Which, of course, makes it more difficult to state one simple rule.

That said the trend is for there to be an emailbox rule – that is, the mailbox rule applied to email.

The Emailbox Rule – or the Mailbox Rule Applied to Email and Other Electronic Message and Communications

Basically, the Mailbox Rule has been held to apply to email and other types of electronic messages in much the same way as the Mailbox Rule applies to paper mail.

The Rule:

There is a rebuttable presumption that once an email or other electronic message has been sent, that it has been received by the intended recipient.

This Emailbox Rule is supported by a line of cases including:

American Boat Company v. Unknown Sunken Barge, 418 F.3d 910 (8th Cir. 2005), which states that there is a “presumption of delivery and receipt of emails properly dispatched.”

Kennell v. Gates, 215 F.3d 825, 828 (8th Cir. 2000), which held that in-house electronic messages are presumed received when properly sent.

United States v. Cary, No. 15-3858 (7th Cir. Mar. 6, 2017), which held that “courts may reasonably presume that electronic messages, once sent, are received.”

Also Ball v. Kotter, 723 F. 3d 813 (7th Cir. 2013) and Couch v. AT&T Servs., No. 13-CV-2004 (DRH)(GRB), 2014 WL7424093.

As a side note, U.S. v. Cary deals with a text message which the defendant’s phone sent to a minor and which the defendant (Cary) says was sent in error, and that anyways there was no proof that the minor had received the message, as she had never responded. Oops, sorry, Cary, the Mailbox Rule applies.

In this day and age of ever aggressive spam filtering, it’s entirely possible that something you sent to someone was not received on their end, or that something you are waiting for but have no received was in fact sent to you, so if you are the sender it behooves you to follow up and check with the recipient to make sure that they have received it; if you are the waiting receiver, check your spam filter.

2 Replies to “The Mailbox Rule and How it Applies to Email”

  1. I’d love to see a follow-up on this about legal methods contracting entities can use to require that delivery be done by reliable means, or that methods be used to prove delivery occurred, before a contract goes into effect. I know this *can* be done, but IANAL so I don’t know how. 🙂

    1. Hi Catherine – it’s very common for parties to send legal documents via certified mail, requesting proof of delivery. As for email, you just ask the recipient to confirm receipt.

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