Due to tax code changes in the Tax Cuts and Jobs Act of 2017, patented works are no longer eligible for capital gain treatment. 

Prior to 2018, IRC Sec 1235 allowed the transfer (other than by gift, inheritance, etc.) of all substantial rights in a patent by an inventor and by certain individuals who acquired their interest before the invention was put into use to be treated as a sale or exchange of a capital asset held more than a year.

The TCJA, amended section 1221(a)(3), effective for dispositions after December 31, 2017, and excludes from the definition of “capital asset” a patent, invention, model or design (whether or not patented), and a secret formula or process. This change applies to the taxpayer who created the property and a taxpayer with a substituted or transferred basis from the taxpayer who created the property (or for whom the property was created). Thus, even though Sec 1235 wasn’t repealed by TCJA, because of the change to Sec 1221, gains or losses from the sale of a patent, etc., will not receive capital gain treatment.