With respect to the time within which an offer must be accepted,

this article, which corresponds to the second part of para. (2) of Art.

18 CISG, distinguishes between written and oral offers.

As concerns written offers, all depends upon whether or not the

offer indicated a specific time for acceptance: if it did, the offer must

be accepted within that time, while in all other cases the indication of

assent must reach the offeror “within a reasonable time having regard

to the circumstances, including the rapidity of the means of

communication employed by the offeror”.

I l l u s t r a t i o n s

1. A sends B an offer on Monday indicating that if B intends to

accept, it must do so by Friday at the latest. B’s acceptance reaches

A on the Monday of the following week. A may reject B’s

acceptance as being too late.

2. A sends B an offer on Monday morning by e-mail, urging B to

reply “as soon as possible”. Although on previous occasions A and B

had already communicated by e-mail, B accepts A’s offer by letter

which reaches A on Thursday. B’s acceptance is too late since under

the circumstances an acceptance by a letter which reaches A three

days after its e-mail was not made “as soon as possible”.

Oral offers must be accepted immediately unless the circumstances

indicate otherwise. An offer is to be considered oral not only when

made in the presence of the offeree, but whenever the offeree can

respond immediately. This is the case of an offer made over the phone

or communicated electronically in real time (e.g. in “chat rooms”).

It is important to note that the rules laid down in this article also

apply to situations where, in accordance with Art. 2.1.6(3), the

offeree may indicate assent by performing an act without notice to the

offeror: in these cases it is the act of performance which has to be

accomplished within the respective periods of time.

For the determination of the precise starting point of the period of

time fixed by the offeror, see Art. 2.1.8; as to the calculation of

holidays falling within that period of time, see Art. 1.12; as to cases of

late acceptance and of delay in transmission, see Art. 2.1.9.