▁capital ▁inv ested ▁in ▁indust ries , ▁and ▁if ▁there ▁was ▁no ▁real istic ▁possibility ▁at ▁all ▁of ▁reaching ▁at ▁least ▁that ▁profit ▁rate ▁som etime ▁in ▁the ▁future , ▁capital ▁would ▁very ▁likely ▁be ▁dis inv ested ▁after ▁a ▁while , ▁since ▁the ▁relevant ▁business ▁would ▁then ▁simply ▁lack ▁commercial ▁vi ability ; ▁altern atively , ▁the ▁business ▁would ▁be ▁taken ▁over , ▁and ▁rest ruct ured ▁to ▁restore ▁an ▁acceptable ▁profit ▁rate . ▁This ▁minimum ▁profit ▁rate ▁applying ▁to ▁new ▁invest ments ▁is ▁closely ▁linked ▁to ▁the ▁r uling ▁interest ▁rates ▁applicable ▁to ▁producing ▁enter pr ises . ▁Marx ' s ▁" general ▁rate ▁of ▁profit " ▁specifically ▁represents ▁the ▁" min imum ▁profit ▁rate " ▁on ▁capital , ▁below ▁which ▁the ▁produ cers , ▁in ▁the ▁normal ▁run ▁of ▁events , ▁cannot ▁stay ▁in ▁business ▁for ▁long . ▁It ▁is ▁neither ▁an ▁empir ical ▁average ▁of ▁many ▁profit ▁rates , ▁nor ▁merely ▁a ▁theoretical ▁ratio , ▁but ▁a ▁real ▁system ic ▁constraint . ▁ ▁Marx ▁and ▁Eng els ▁explicitly ▁denied ▁that ▁in ▁reality ▁total ▁product - value ▁would ▁be ▁equal ▁to ▁the ▁total ▁of ▁production ▁prices ▁( see ▁prices ▁of ▁production ). ▁Such ▁an ▁" account ing ▁identity " ▁was ▁ruled ▁out ▁in ▁the ▁real ▁world ▁by ▁contin ual ▁variations ▁in ▁labour ▁product ivity ▁and ▁because , ▁at ▁any ▁time , ▁no ▁compet itive ▁force ▁existed ▁that ▁could ▁exactly ▁cancel ▁out ▁the ▁difference ▁between ▁goods ▁sold ▁above ▁value ▁and ▁goods ▁sold ▁below ▁value . ▁It ▁was ▁also ▁ruled ▁out ▁by