The US Supreme Court recently heard arguments on whether a computerised system for managing settlement risk constitutes patent-eligible subject matter, a question that had left an en banc Federal Circuit divided and without a majority opinion. While this case is similar in many respects to Bilski v Kappos, neither Bilski nor subsequent Supreme Court and Federal Circuit decisions have articulated a definitive test to determine whether computer-implemented inventions are eligible for patenting. Perhaps perceiving a need for such a test, the justices focused several questions on where and how a line should be drawn between patent-eligible and patent-ineligible subject matter.