substantial lessening of competition

Mere acquisition by one corporation of the stock of a competitor, even though it result in some lessening of competition, is not forbidden; the act deals only with such acquisitions as probably will result in lessening competition to a substantial degree, that is to say, to such a degree as will injuriously affect the public. Obviously such acquisition will not produce the forbidden result if there be no pre-existing substantial competition to be affected; for the public interest is not concerned in the lessening of competition, which, to begin with, is itself without real substance.