Definition
Assumpsit (also rendered "a sumpsit" in older typesettings) is a common law form of action used to recover damages for the breach of a simple contract — that is, a contract that is neither under seal nor a matter of record. The action lies where one party has undertaken a promise, express or implied, and failed to perform it.
Two principal forms existed:
1. Express assumpsit: The undertaking arises from language that is distinct and definite — a clearly stated promise by the defendant.
2. Implied assumpsit: No formal promise was spoken or written, but the law infers one from the conduct of the party or the circumstances of the case. This fiction allowed the action to reach situations that would otherwise fall outside the scope of formal contract remedies.
Common Confusion
Assumpsit is frequently confused with debt and covenant, the two older common law actions it eventually displaced or supplemented. Debt required a fixed, liquidated sum; covenant required a sealed instrument. Assumpsit filled the gap — it reached unliquidated damages and unsealed agreements — and over time expanded far beyond its original scope to become the dominant vehicle for contract recovery. Researchers must be alert to which action was actually pleaded in historical records, since the procedural consequences differed substantially.
Recognized Forms
/SUBTYPES
General assumpsit: Brought on an implied promise; historically used with the common counts (money had and received, money lent, quantum meruit, quantum valebant, account stated). The implied promise was often a legal fiction.
Special assumpsit: Brought on an express promise; required pleading the specific terms of the agreement and the precise breach.
Why It Matters in Research
Assumpsit is among the most consequential terms a researcher will encounter in pre-twentieth-century common law materials, and its importance extends well beyond contract law. Several research traps exist:
Spelling and rendering: Historical sources spell this term inconsistently. "A sumpsit," "assumpsit," "assumsit," and abbreviated forms all appear. Search strategies must account for this variation, particularly in digitized court records and older reporters.
The implied promise fiction: Much of equity jurisprudence and quasi-contract doctrine grew out of the general assumpsit framework. When reading 18th and 19th century decisions involving "money had and received" or "unjust enrichment," the underlying action is typically general assumpsit. Researchers working in restitution or quasi-contract must understand this lineage.
Displacement of older actions: As assumpsit expanded, it absorbed much of what debt and account had formerly covered. A case that looks like a debt dispute in its facts may be decided entirely on assumpsit principles — this affects both the law applied and the remedies available.
Abolition of forms of action: Most American jurisdictions abolished the forms of action through code pleading in the 19th century (following the Field Code of 1848 in New York) and later through the Federal Rules of Civil Procedure in 1938. After abolition, assumpsit as a procedural category disappears — but the substantive principles it carried (implied contract, quasi-contract, unjust enrichment) survive under new labels. Researchers crossing the pre/post-code boundary must track this conceptual migration.
Corpus connections: Cases decided before code pleading reforms will identify the form of action as a threshold matter. Understanding whether a court is resolving a special or general assumpsit claim determines what elements the court is actually testing, even if those elements are not labeled as such in the opinion.
Historical Dictionary Support
Black's Law Dictionary captures the essential structure: assumpsit reaches non-performance of a parol or simple contract and divides into express and implied forms. The definition is serviceable but compressed. It does not fully convey the scale of the action's historical importance — by the 18th century, assumpsit had become the workhorse of commercial litigation, and the implied promise device used in general assumpsit was understood by courts and practitioners as an acknowledged fiction, not a genuine factual finding. Black's treatment also does not flag the post-abolition transformation, which is the most practically significant issue for researchers working across historical periods.
The citations in Black's (7 Term Rep. 351; 3 Johns. Cas. 60) point to genuine English and early American authority and reflect the period when assumpsit doctrine was fully mature.
Jurisdictional Note
Assumpsit as a named form of action is historical in all American jurisdictions, abolished by code pleading reforms that occurred at different times across states during the 19th century. The substantive law it carried — particularly quasi-contract and implied contract — remains active and jurisdiction-specific in its modern form. English law followed a parallel path with the Judicature Acts of 1873–1875.