When parties to a contract make promises to perform their obligations, and one party reasonably relies on the other party’s promise—but the party making the promise fails to perform, causing harm or loss to the party who relied on the promise—the party who relied on the promise to perform is said to have relied to its detriment.

This legal concept is called detrimental reliance. Detrimental reliance may serve as a substitute for consideration, and make an otherwise unenforceable contract enforceable.

Thus, detrimental reliance is a legal concept based on fairness (known as equity or equitable), and is equivalent to contractual promissory estoppel (due to the other party’s reliance, the party who did not keep its promise is prohibited from challenging the enforceability of its promise).

Detrimental reliance is not a separate tort cause of action.

In Alaska, the legal concept of detrimental reliance, also known as promissory estoppel, is recognized and can be used to enforce a contract that may otherwise lack consideration. This principle applies when one party makes a promise that the other party relies upon, and as a result of this reliance, the latter party suffers a loss or harm when the promise is not fulfilled. The reliance must be reasonable, and the resulting harm must be significant enough to warrant enforcement of the promise. Detrimental reliance ensures that a party cannot renege on a promise if the other party has taken action based on the belief that the promise would be honored. This concept is rooted in principles of fairness and equity, aiming to prevent injustice due to unfulfilled promises. While detrimental reliance is not a separate cause of action in tort, it is a doctrine that can be invoked in contract disputes to hold parties accountable for their promises in Alaska.