Assumpsit is an express or implied agreement to perform an oral contract. An express assumpsit is where one undertakes verbally or in writing, not under seal, or on record, to perform an act, or to pay a sum of money to another.
An implied assumpsit is where one has not made any formal promise to do an act or to pay a sum of money to another, but who is presumed from his conduct to have assumed an obligation to do the just and fair thing. Common or indebitatus assumpsit is brought for the most part on an implied promise. Special assumpsit is founded on an express promise or undertaking.
