A recent Australian Federal Court decision limits the scope of patent protection for business methods implemented by computer. The invention in question related to securities investing and, more specifically, to construction and use of passive portfolios and indexes.
The court denied patentability, stating:
"The implementation of the method of the claimed invention by means of a computer, at the level articulated in claim 1, is no more than the modern equivalent of writing down the index on pieces of paper. On the face of the Specification, there is no patentable invention in the fact that the claimed method is implemented by means of a computer. The Specification asserts a patentable invention, not in the use of the computer, but in the particular series of steps that give rise to the generation of the index. Those steps could readily have been carried out manually. The aspect of computer implementation is nothing more than the use of a computer for a purpose for which it is suitable. That does not confer patentability.
The enquiry into what constitutes a patentable invention is still evolving. It is not to be tied to particular notions of what was understood to be a manufacture at any particular point in time. However, while new developments in technology might be seen to widen the notion of what is patentable, the modern availability of computers as a standard means of implementing arithmetic or computational processes, which could have been implemented manually in the past, does not carry with it any broadening of the concept of a patentable invention."
See Research Affiliates LLC v Commissioner of Patents  FCA 71