R2d § 74
Settlement of Claims
(1) Forbearance to assert or the surrender of a claim or defense which proves to be invalid is not consideration unless (a) the claim or defense is in fact doubtful because of uncertainty as to the facts or the law, or (b) the forbearing or surrendering party believes that the claim or defense may be fairly determined to be valid. (2) The execution of a written instrument surrendering a claim or defense by one who is under no duty to execute it is consideration if the execution of the written instrument is bargained for even though he is not asserting the claim or defense and believes that no valid claim or defense exists.
Professor's notes
Elements: (1) forbearance to assert or surrender of an invalid claim is not consideration unless (a) the claim is in fact doubtful because of uncertainty as to the facts or the law, OR (b) the forbearing or surrendering party believes the claim may be fairly determined to be valid; (2) the execution of a written instrument surrendering a claim by one who is under no duty to execute it is consideration if the recipient bargained for it.
Common misunderstanding: students think surrender of any claim is consideration. Surrender of a knowingly frivolous claim is not: that would be the law buying off blackmail. The good-faith plus reasonable-basis test (subsection 1(b)) is the floor.
Pair with § 73 (pre-existing duty): both rules police the bargain element from the "no real exchange" side.
Text
R2d § 74. Settlement of Claims.
(1) Forbearance to assert or the surrender of a claim or defense which proves to be invalid is not consideration unless
(a) the claim or defense is in fact doubtful because of uncertainty as to the facts or the law, or
(b) the forbearing or surrendering party believes that the claim or defense may be fairly determined to be valid.
(2) The execution of a written instrument surrendering a claim or defense by one who is under no duty to execute it is consideration if the execution of the written instrument is bargained for even though he is not asserting the claim or defense and believes that no valid claim or defense exists.