Bernard Bilski and Rand Warsaw filed a patent application with the U.S. Patent and Trademark Office (PTO). The application sought patent protection for a claimed invention that explains how buyers and sellers of commodities in the energy market can hedge against the risk of price changes. The key claims are claims 1 and 4. Claim 1 describes a series of steps instructing how to hedge risk. Claim 4 puts the concept articulated in claim 1 into a simple mathematical formula. The remaining claims describe how claims 1 and 4 can be applied to allow energy suppliers and consumers to minimize the risks resulting from fluctuations in market demand for energy. The PTO rejected the patent application, holding that it merely manipulates an abstract idea and solves a purely mathematical problem. The U.S. Court of Appeals affirmed. Petitioners Bilski and Warsaw appealed to the U.S. Supreme Court. Issue is the petitioners' claimed invention patentable?