IP entrepreneurs frequently seek to acquire intellectual property from other entities, whether as a straight license or assignment, or as party of a merger or acquisition of assets. If a substantial portion of the value relies upon the intellectual property, the entrepreneur needs substantial due diligence to avoid buying the cow rather than just the milk.
First, intellectual property is subject to wide variations of valuation. Never take the seller’s word for it. Proven sales or established licensing rates help. Experts exist to give a fair market appraisal, to the extent that it can be done, for intellectual property.
Second, intellectual property can disappear. Patents and trademarks can be invalidated or rendered unenforceable. Copyright registrations can be invalidated, and/or the copyright protectable expression can be found to be non-existent.
Third, ownership is rarely clear cut. Ownership where employees or contractors are involved can be a nasty mess requiring tracing back through each person and each agreement to determine what, if anything, was effectively assigned, what was obligated to be assigned, or what might be hanging out free and clear. Like buying the cow, when buying intellectual property due diligence can sometimes show that the milk is free.