ould indicate that the OSS/BSS software markets are reaching a mature phase, where one could expect a more stable development afterwards. On the other hand, a new cycle of vertical disintegration and de-concentration could occur in the future. The results also indicate that the market segments of the OSS/BSS software industry might be in different evolutionary stages. If the indus- try is considered as a whole, it may be judged to be in the mature phase. However, six market segments indicate an opposite development from the rest of the industry by, for example, showing a stable or even growing number of firms. Within an industry there thus seems to be segments which evolve differently. This might be due to the different ages of these segments; relatively newer market segments could be expected to behave differently from the phase the rest of the industry is in. OSS/BSS in the Vertical Software Market Evolution Model A vertical software market can be analyzed with the vertical software market evolution model and the industry lifecycle model. Usually the market is identified to be in similar phases according to both of these models. That is, the market is found to be in growth phases in both, in mature phase in both, or in between in both models. However, in some cases the vertical software market evolution may be stopped causing the software vendors to allocate their resources to some other market with higher expected revenues and thus causing transition to a mature phase in terms of the industry lifecycle model. Thus the previous result suggesting that most of the OSS/BSS market segments are in the mature phase of the industry lifecycle model does not necessary imply that the vertical software market would as well be in the last (mature) phase. The current phase of the vertical software market evolution manifests itself in a number of different indicators, among which one can distinguish software spending by the operators, the channel of software delivery, market concentration, etc. Some of these indicators are a