Earlier this month, Led Zeppelin scored a big victory in a longstanding copyright infringement case. For years, the legendary rock band faced copyright infringement allegations against “Stairway to Heaven,” one of its biggest hits. Specifically, a rival band’s guitarist argued that Led Zeppelin took the infamous “Stairway to Heaven” guitar introduction from another song. However, the 9th Circuit ruled in favor of Led Zeppelin, deciding that “Stairway to Heaven” does not infringe a copyright.

Copyright Act of 1909 vs. Copyright Act of 1976

The rival band, Spirit, wrote and registered a copyright in the sheet music for “Taurus,” one of its songs. The song features a guitar riff that is strikingly similar to the “Stairway to Heaven” introduction. However, “Taurus” registered as a copyright in 1967 under the Copyright Act of 1909, which limited music copyrights to sheet music. The Copyright Act of 1976 included registrations for sound recordings; however, Spirit’s song fell under a previous version of the Act. As such, Spirit’s copyright extended to the sheet music, and the sound recording could not be used in court.

Under US copyright law, infringement occurs when two works are similar, and the infringing party had access to the original work. The 9th Circuit previously used an “inverse ratio rule” between the factors. In other words, if an infringing party enjoys increased access to a work, the similarity factor has a lowered standard of proof. In the case of Led Zeppelin vs. Spirit, the bands toured together prior to the release of “Stairway to Heaven.” However, the 9th Circuit decided that an increasingly online world renders the “inverse ratio rule” outdated, and overturned the rule completely. For Led Zeppelin, this meant that “Stairway to Heaven” does not infringe Spirit’s copyright.

The result of the case is a much stricter standard of copyright infringement for sound recordings. However, musicians can improve their situation by registering their works with the Copyright Office. By doing so, substantial statutory damages are available for copyright infringement. Or, at the very least, an infringer is much more likely to settle when faced with statutory damages.