State Street Bank & Trust Co. v. Signature Financial Group, Inc.
149 F.3d 1368 (Fed. Cir. 1998)

  • Congress passed a law saying that you would get a tax break if you set up a stock fund in a certain way. Signature developed a process and a computer program to help manage a portfolio in order to best take advantage of the tax break. They applied for a patent on their method.
    • It was really just a method for how to trade stock. But the patent application was written in such a way to make it sound like a 'system' so it would meet the requirements of Diamond v. Diehr (450 U.S. 175 (1981)).
  • The Trial Court found Signature's patent invalid. Signature appealed.
    • The Trial Court found that the method was nothing more than a math equation, and math equations are not patentable subject matter.
      • See Gottschalk v. Benson (409 U.S. 63 (1972)).
  • The Appellate Court reversed and allowed the patent.
    • The Appellate Court found that the patent was valid under the useful results test.
      • The useful results test holds that, "the transformation of data representing discrete dollar amounts by a machine through a series of mathematical calculations into a final share price, constitutes a practical application of a mathematical algorithm, formula, or calculation, because it produces 'a useful, concrete, and tangible result.'"
    • Basically, the useful results test collapses the concept of patentable subject matter into the utility requirement.
  • This case was overturned by In Re Bilski (545 F.3d 943 (2008)), which dumped the useful results test, in favor of the machine or apparatus test which holds that in order to be patentable subject matter a patent for a method must:
    • Be tied to a particular machine or apparatus, or
    • Transform a particular article into a different state or thing.