Led Zeppelin defeats Spirit appeal in 'Stairway to Heaven' case

In an appellate ruling that may very well have an affect on music copyright claims going forward, the 9th Circuit Court of Appeals upheld on Monday a jury's verdict that Led Zeppelin's "Stairway to Heaven" did not infringe upon Spirit's "Taurus." (Notably, none of the bandmembers of Spirit were invovled in the case- rather, one of the current rights holders of the song, Michael Skidmore, an heir of one of the band members, brought the case).
Led Zeppelin previously won the matter at a jury trial in 2016, but the Plaintiffs filed an appeal citing errors in the judge's instruction to jurors. That appeal was heard by a three judge panel in the 9th U.S. Circuit Court of Appeals and a new trial was granted. However, Led Zep then appealed that decision.
This time, Led Zep was victorious. In the The 9th Circuit Court of Appeals, a panel of 11 judges voted 9-2 in Zeppelin's favor on Monday, stating that jury instruction errors, if they did exist, were immaterial. Additionally, The court overturned the so-called “inverse ratio rule,” a rule that has controlled copyright cases in the 9th Circuit for the last 43 years. That rule, which was only used in the 9th circuit, stated that the more access to a source material could be shown, the less requirement was there for a plaintiff to show striking similarity to an infringing work. In part, the court stated in its ruling, "We have never extended copyright protection to just a few notes. Instead we have held that ‘a four-note sequence common in the music field’ is not the copyrightable expression in a song.”