Bilski v. Kappos
The 2010 US Supreme Court ruling that struck down a patent on risk hedging as an abstract idea, while leaving business method patents alive.
Bernard Bilski and Rand Warsaw sought a patent on a method for hedging price risk in energy trading. The patent office refused, and in 2008 the Federal Circuit adopted a single test: a process is patentable only if it is tied to a machine or transforms something physical.
The Supreme Court agreed with the outcome but not the test. Machine-or-transformation was a useful clue, not the whole answer, and business methods weren't excluded as a category. Bilski's claim fell anyway as an abstract idea. What counted as an abstract idea the court declined to say, which bought four years of uncertainty until Alice answered the question in 2014 and software patents started falling by the thousand.