The IRS places restrictions on loss deductions for Section 197 intangible assets in certain circumstances. 

A loss deduction is not allowed on disposition, abandonment, or worthlessness of an intangible if any other Section 197 intangible was acquired in the same transaction and a taxpayer still has the other intangible. If the latter is true, the unallowed loss is reallocated to the retained intangible. Thus, the cost of many Section 197 assets must continue to be amortized, although they become worthless for one reason or another.