The Mailbox Rule and Related Rules
Prof. Tom W. Bell
NB: For a better and more recent version of this document, please see The Mailbox Rule and
Related Rules [PDF format].
I. Rules for Forming Contracts via Correspondence
- Generally, acceptance is effective when sent, regardless of whether it
reaches the offeror. See Restatement (2nd) § 63.
- But note that exceptions apply (see id.):
- if the offer provides otherwise,
- if acceptance is not made in a manner and by a medium invited
by the offer, or
- to acceptance under an option contract, which is effective
upon receipt by the offeror.
- Note also that id. § 40 modifies the mailbox rule when an
earlier rejection arrives before a later acceptance (see below).
- Generally, revocation is effective when received by the offeree. See
Restatement (2nd) § 42. But note that an exception applies in the case of
option contracts, per id. § 37.
- Generally, rejection or counter-offer is effective when received by the
offeror. See Restatement (2nd) § 40. But note that, per id., an
acceptance sent after an otherwise effective rejection or counter-offer:
- operates only as a counter-offer if the offeror receives it after
the earlier-sent rejection or counter-offer (thus providing an exception to the
mailbox rule); and
- operates as an acceptance if the offeror receives it before the
earlier-sent rejection or counter-offer.
- A useful mnemonic: Acceptance on answer; revocation or rejection on
receipt.
II. Applying the Rules
- Reading the illustrations: In the illustrations that follow, the
vertical distance between the offeror and offeree represents the space across
which they communicate. Time progresses from left to right along the horizontal
axis. Relatively slow communications appear as slanted lines, therefore, while
relatively instantaneous ones appear as vertical lines. Unless otherwise noted,
"rejection" stands for "rejection or counter-offer."
- Caveats: These illustrations address generic contract formation; that
is, they assume that the offerors have not put special conditions on the proper
mode of acceptance, that acceptance is in a manner and by a medium invited by
the offer, and that option contracts are not at issue.
- Standard acceptance (effective at "X")
OFFEROR: offer receipt of effective acceptance
\ /
\ /
\ X
OFFEREE: acceptance
- Lost acceptance (effective at "X")
OFFEROR: offer
\ ? acceptance lost
\ /
\ X
OFFEREE: acceptance
- Revocation trumped by earlier acceptance (eff. at "X")
OFFEROR: offer revocation receipt of effective acc.
\ | /
\ |/
\ /
\ /|
\ X v
OFFEREE: acceptance rec't of ineffect. revocation
- Rejection trumped by earlier acceptance (eff. at "X")
receipt of receipt of
OFFEROR: offer ineff. rej. effective accept.
\ ^ /
\ | /
\ |/
\ /
\ /|
\ X |
OFFEREE: acceptance rejection
NB: But see Comment c and Illustration 7 to Restatement (2nd) §
63, providing that the offeree may be estopped to enforce the contract against
an offeror who reasonably relies on the earlier-received rejection.
- Rejection trumped by faster revocation (effective at
"X")
Offeror: offer rev. rec't of ineff. reject'n
\ | /
\ |/
\ |
\ /|
\ / v
OFFEREE: rejection X-rec't of effective revocat'n
- Revocation trumped by faster rejection (effective at
"X")
OFFEROR: offer rev. X-rec't of effective reject'n
\ \ ^
\ \|
\ |
\ |\
\ | \
OFFEREE: rejection receipt of ineff. revocat'n
- Rejection trumped by later acceptance (eff. at "X")
receipt of receipt of
OFFEROR: offer eff. accept. ineffective rejection
\ ^ /
\ | /
\ |/
\ /
\ /|
\ / X
OFFEREE: rejection acceptance
- Acceptance trumped by earlier rejection (eff. at "X")
rec't of rec't of
OFFEROR: offer eff. rej. ineffective acceptance
\ X /
\ / /
\ / /
\ / /
\ / /
\ / /
OFFEREE: rejection acceptance
NB: Even though here the acceptance is sent before the receipt of
the rejection, Restatement (2nd) § 40 modifies the mailbox rule to provide
that a prior-sent rejection or counter-offer will, if received before the
putative acceptance, render that acceptance a mere counter-offer.
- A Puzzle: Rejection, Revocation, or Acceptance?
rec't rec't of
OFFEROR: offer revocat'n of rej. acceptance
\ \ ? /
\ \ / /
\ \ / /
\ /\ /
\ / /
\ / ? \
OFFEREE: rejection acc. ?-receipt of
revocation
NB: E, supra, suggests that the acceptance sent prior to the
receipt of the revocation will trump that revocation. G, supra, suggests that
the prior-received revocation will trump the later-received rejection or
counter-offer. J, supra, suggests that the rejection or counter-offer sent
prior to and received before the acceptance will trump that
acceptance.
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The Mailbox Rule and Related Rules -
tomwbell@tomwbell.com - v. 2002/08/17