The parties negotiated a commercial sublease of office space in Manhattan. Their letter agreement stated in substance that the sublease would be "null and void and of no further force and effect unless, on or before November 30, 1987," the sublessor (Oppenheim, Appel, Dixon & Co.) delivered to the sublessee (Oppenheimer & Co., Inc.) the prime landlord's written consent to the sublease. The clause specified that this condition was for the sublessee's benefit and could be waived by the sublessee. As the deadline approached, the sublessor communicated that the landlord had agreed in principle, and forwarded a facsimile/telex from the landlord's agent indicating consent subject to documentation. However, the formal written consent from the landlord was not executed and delivered to the sublessee by November 30. It was delivered several days later in early December. On December 1, the sublessee notified the sublessor that the condition had not been satisfied and that the sublease was therefore null and void. Litigation followed: the sublessor contended there had been substantial performance or that the communications sufficed to meet the condition; the sublessee argued the express condition required strict compliance and was unmet. The lower courts split, and the New York Court of Appeals granted review.
Whether the doctrine of substantial performance can satisfy an express condition precedent that required delivery of the prime landlord's written consent by a date certain, and, if not satisfied, whether the sublease was null and void such that the sublessee had no duty to perform.
Express conditions precedent—events that the parties explicitly make prerequisites to the formation or duty of performance, often signaled by language such as "if," "unless," "until," and "null and void unless"—must be literally performed; substantial performance of an express condition is insufficient. The nonoccurrence of an express condition prevents formation of the contract or the accrual of the duty it conditions, unless the condition is excused by waiver, estoppel, prevention, or a limited equitable doctrine avoiding disproportionate forfeiture when the condition is not a material part of the agreed exchange. Courts ascertain whether language creates an express condition by focusing on intent as expressed in the contract's words and structure.
The landlord's written consent was not delivered by the contractual deadline, so the express condition precedent failed. Substantial performance cannot cure failure of an express condition. No waiver, estoppel, prevention, or disproportionate forfeiture applied. The sublease was therefore null and void, and the sublessee had no contractual obligation to perform.
The court first identified the operative clause as an express condition because it used strong conditional language—"null and void" unless the sublessor delivered the landlord's "written consent" by a specified date—and allocated the benefit of the condition to the sublessee. Given that intent, strict compliance was required. The sublessor's production of a telex/facsimile from the landlord's agent stating consent in principle did not satisfy the explicit requirement of delivery of the landlord's written consent instrument by the deadline. Even assuming the landlord had orally consented or consented subject to documentation, the parties bargained for the certainty of written consent delivered by a date certain; the agreed formality and timing were part of the condition itself. The court rejected the argument that substantial performance should apply, explaining that doctrine mitigates breaches of promises or constructive conditions but does not excuse the nonoccurrence of an express condition, which by definition is an agreed prerequisite to duty. The court also declined to rest decision on whether the condition was one of contract formation or performance, observing that the consequence is the same: without the condition, no duty arises. Further, the court found no waiver because the sublessee did not intentionally relinquish the protection of the condition; the agreement made the condition waivable solely by the sublessee, and it never waived it. Estoppel failed because the sublessor did not show misleading conduct by the sublessee or detrimental reliance that would make enforcement inequitable. Finally, the court considered and rejected disproportionate forfeiture. The missed deadline resulted from the sublessor's failure to obtain and deliver the specified consent on time; the parties were sophisticated commercial actors who allocated this risk and expressly provided that the sublease would be void absent timely delivery. The court was unwilling to rewrite the bargain to save the sublessor from the consequence of a condition that was central to the sublessee's protection. Because the express condition failed and no recognized excuse applied, the sublease never became enforceable against the sublessee.
Oppenheimer is a cornerstone case on express conditions precedent. It teaches that courts will enforce clear conditional language as written, requiring literal compliance with both form and timing. For students, it sharpens the distinction between promises/constructive conditions (where substantial performance may soften breach) and express conditions (where it does not). The case also highlights recognized escape hatches—waiver, estoppel, prevention, and disproportionate forfeiture under the Restatement—while emphasizing their narrow application. Practically, Oppenheimer is a drafting lesson: if parties make a protection a condition with "null and void unless" and a date certain, courts will not substitute substantial performance or equitable gloss to rescue a missed condition.
Oppenheimer crystallizes a core contracts lesson: when sophisticated parties intentionally make an event an express condition to duty or formation, courts will enforce the condition as written. The decision refuses to blur the line between promises and express conditions by importing substantial performance, and it applies potential excuses only with discipline.