Opponents identify another possible harm from copyright extension: loss of productive value of private collections of copyrighted works. A person who collected copyrighted works that would soon "go out of copyright," intending to re-release them on copyright expiration, lost the use of his capital expenditures for an additional 20 years when the Bono Act passed. This is part of the underlying argument in Eldred v. Ashcroft .  The Bono Act is thus perceived to add an instability to commerce and investment, areas which have a better legal theoretical basis than intellectual property, whose theory is of quite recent development and is often criticized as being a corporate chimera. Conceivably, if one had made such an investment and then produced a derivative work (or perhaps even re-released the work in ipse ), he could counter a suit made by the copyright holder by declaring that Congress had unconstitutionally made, ex post facto , a restriction on the previously unrestricted.