Abstract
The text deals with the concept of the discount submitted by a candidate contractor tendering for a public works project. In accordance with prevailing conceptions, the quantity of the discount is perceived as being the amount of monetary compensation the candidate building contractor is willing to forgo for the sake of emerging as the winner of the tender. The text argues on the contrary that the discount is an objectively measurable magnitude. Specifically it is equal to the algebraic difference of the absolute surplus value that could be appropriated by the public works contractor minus the quantity of relative surplus value by virtue of which he is able to recoup the amount of discount submitted in the tender.