Promissory Estoppel

Promissory estoppel allows enforcement of a promise that would otherwise fail for lack of consideration, when the promisor should reasonably have expected the promisee to rely on it and the promisee did rely, to their detriment. It is contract law's response to broken promises that produce real-world harm: relocating for a job offer, declining other opportunities, investing in reliance on an assurance.

Under California law (following Restatement (Second) of Contracts §90), four elements are required: a clear and unambiguous promise, reasonable and foreseeable reliance, actual reliance, and injustice that can only be avoided by enforcement. Each element is rigorously tested, vague encouragement or aspirational language usually fails the "clear and unambiguous" threshold.

The remedy is often limited to the reliance interest, what the promisee actually lost, rather than the full expectation damages a binding contract would yield. Courts use this flexibility to balance fairness with discouraging weak claims. In employment, real estate, and family business contexts, promissory estoppel claims are common and frequently decided on summary judgment based on the strength of the documentary record.