perations of these firms increases for the above mentioned reasons. 3. As a result of the two above hypotheses, the industry consolidates, as fewer vendors have a greater market share of the industry. In order to examine the concentration of the software market, commercial data from Dittberner Associates, Inc was analyzed for the years 2000, 2002, 2005 and 2006. The OSS/BSS companies and their revenue data were organized into thirteen segments presented in Fig. 1 of Chap. 4. The number of companies in each segment, the HHI index value for the industry segments, and the number of companies deploying vertically integrated business strategies for each of the year data was provided. The HHI is calculated by summing up the squares of individual firm market shares from all firms operating in the market. It thus gives a greater weight to firms with greater market shares. The mathematical form of HHI is: HHI = In (1) Si is the market share of Firm i, and n is the number of firms in the market. The value of HHI is thus positive, and its maximum is 10,000 when a single firm has a market share of 100%, which is the case in a monopoly situation. The total number of companies operating in the market at different points in time is shown in Table 2. Table 3 represents the number of companies operating in the thirteen segments and the changes in the number of vendors for the time periods. A single vendor may have operated, i.e., received revenue, from one or several segments. In general, the number of vendors operating in the industry (including service providers) dropped from its peak of 232 companies in 2002 to 196 companies Table 2 The total number # Companies of analyzed companies Y 2000 operating in the market Y 2002 (years 2000-2006) Y 2005 Y 2006 Table 3 Changes in the number of companies in the OSS/BSS market segments in the years 2000-2006 Segment Y 2000 Y 2002 Y 2005 Y 2006 - -22.2 -47.1 -35.3 -22.2 - 14.3 - 12.0 - 13.8 - 19.4 - 14.3 Table 4 Changes in the HHI index in the OSS/BSS market segments in the years 2000-2006