Abstract
The aim of this paper is to build a investment function model to describe the computer investment of the financial institutes. This model is based on the life cycle of the information system, and is a kind of replacement investment theory. The difference between this model and the other former replacement investment functions is whether there is depreciation or not. In this model, the capital doesn't decrease before the life cycle of the information system expire. I measured the investment function positively using econometric methods. This model will enable us to predict the investment of the information systems of the financal institutes.
