Both the passive investment scenarios and the Coasian joint control scenarios require an analysis of the relevant market since they operate under the assumption that the acquiring firm and the target firm are rivals. In order to determine if they are rivals one must define the market in which they operate.
 In this case the evidence of the relevant market came largely from three competition economists – each party had instructed their own economists – and two advertising executives – one called by the merging parties and the other by the Commission.
 The experts were far apart on some of the core issues. Nevertheless let us first consider what they agreed on before we examine what kept them apart.
 Radio markets are what are referred to in the literature as dual sided markets. Radio stations compete on the one side of the market for listeners and on the other side for advertising revenue. In this case the economists are all agreed that the competition problems that the merger might create are not to be found in the market for listeners, since all are free- to- air and, hence, there is no danger that post merger the costs of listening will increase or the supply of airtime be reduced, but rather its effect on advertising rates. Kaya FM, like all the Primedia stations is privately held and commercially driven and hence relies on advertising revenue for its existence.
 Although the market is dual sided there is a relationship between competition for listeners and revenue from advertising. Advertisers’ willingness to pay a certain rate for a slot depends on the value they perceive in the audience a station can offer it.
 For this reason one might expect a tendency for radio stations wanting to attract the same listeners to become more homogenous with the market dictating the most successful format for a particular type of audience. However, there is constraint on the ability of stations to optimise formats (the parties differ on how large that constraint is).21 In order to broadcast a station needs a licence issued by the Independent Communications Authority of South Africa (“Icasa”) and in issuing licences, Icasa requires broadcasters to comply with prescribed format obligations. In this case for instance, Highveld is required to play ‘adult contemporary music’ whilst Kaya is licenced to play ‘adult African contemporary music’. Radio stations further require frequencies on which to broadcast and these are also allocated as part of their licence conditions. Frequencies may be national or restricted to a particular geographic area. Highveld and Kaya FM are both restricted in terms of the frequencies allocated, to broadcasting in an area that corresponds largely with the provincial area of Gauteng. Within this area other stations broadcast. Some are regional in character because of the frequency limitations imposed upon them (e.g. Jacaranda an adult contemporary music station and Classic FM, an adult classical music station), while others are licenced to broadcast nationally, but can also be received by listeners within the Gauteng area.
 This is where the consensus among the experts diverges.
 The case for the merging parties is that these constraints serve to so differentiate stations that they do not conform to being ready substitutes, with the result that in the advertising market, stations may compete with a host of imperfect radio substitutes and with other forms of media such as print and television. The result of this analysis is to create a market so narrow that no station has any competition or one so wide, that all stations compete with one another and with other media platforms such as television or print, so that the merger of two regional radio stations will confer limited market power opportunities on the firms in question. The merging parties’ expert, Dr Theron, argued that she was not contending for each station being a monopoly of its own. What she in fact meant is somewhat confusing because in a supplementary report she repeated the assertion that all radio stations might be in a separate market.22 If that contention is correct it would make each station a monopoly.
 The Commission’s market definition expressed in its expert report is “the LSM 6-10 audience for advertisers, in the Gauteng market for adult contemporary music stations, broadcasting predominantly in English.”23
 Based on this definition it says there are two possible markets conceptions of the market here (i) a narrow market in which the only participants are Kaya FM, Highveld and Jacaranda; (ii) a wider market in which it contemplates the possibility that Metro FM, YFM and 5FM may be included, although it has reservations about this.24
 The objection to the inclusion of SABC owned 5FM, and the privately owned youth station YFM, is that they predominantly target youth, unlike Kaya and Highveld. The objection to the inclusion of Metro FM is that it is a national broadcaster, and including it would mean that one is not sufficiently sensitive to advertisers’ reluctance to use stations for whom their would be wastage, if they were interested in only targeting a Gauteng audience. The Commission also rules out other language stations (all SABC’s so called African language stations) and highly focussed stations (Classic FM). The Commission also does not include stations that are not primarily music stations and for that reason does not include Primedia’s other Gauteng flagship, 702 or SA FM the SABC English language station.
 The primary reason for the Commission excluding the stations that it does from the relevant market is that advertisers will not pay for audiences who are not part of their target market or, as the industry refers to it, ‘wastage’. The Commission suggests that the three stations that comprise its narrow market, target an audience similarly situated, both demographically and geographically, and they are thus the closest and most direct competitors of one another.25 Any other station, albeit that it may broadcast into the Gauteng region, is less similar and leads to wastage either because of its geographic sweep or demographic profile. In this the Commission relies heavily on its advertising expert Gordon Muller.
 However this evidence - that concerns over wastage make certain stations imperfect substitutes and thus means they can be excluded from the relevant market - is heavily disputed by the merging parties’ advertising expert, Paul Wilkins, whose thesis is that all stations are potential substitutes; it only depends on what you have to pay for your target audience. On his version, rates even as advertised, are in practice highly negotiable, and so from the advertisers’ point of view, concerns that audiences might be wasted are in practice not true; if the price is right for the audience you want there is no wastage. As he put it in his witness statement:
“I believe that the industry is generally aware of the applicable ratios of value as between the various media types and that prices are affected by this awareness, as negotiations occur in this context.” 26
 Although the Commission’s preference was for the narrower market it did appear to concede that the market could be capable of being more widely populated than its preferred trio, and hence it conceived as well of the wider market that might include 5FM, YFM and Metro FM.27
 In his original report the Commission’s expert, Dr Roberts, provided for the market shares in his wider market (i.e. including Metro, 5FM and YFM) based on their total advertising revenues, during the course of hearings, he altered his methodology and provided for different market shares by taking into account ‘weighting up’ for Gauteng listeners. As we understood this term, advertisers would, even if they were national, ‘weight up’ for Gauteng audiences as they are considered more valuable. The conclusion reached after conducting the ‘weighting up exercise’, revealed in a new revised table , exhibit 32, was that the market shares as originally reflected in Table 8 of his witness report, of Metro, 5FM and Jacaranda declined, while those of the other three, particularly Highveld, Kaya and YFM significantly increased.28
 Besides the weighting up exercise in Exhibit 32, during the course of his testimony Roberts introduced several further permutations to the market share calculations in his witness report. Some were based on the number of hours listened to ( Exhibit 31) another (Exhibit 33), was a series of permutations to deal with age profiles, seemingly performed as a response to Primedia’s expert’s criticism. The interminable tables and graphs handed in by experts during the course of proceedings has thrown little more light on the matter and considerably more mud. It suggests the degree of uncertainty inherent in this debate over market definition, who is in that market once defined and then still, how to slice up what proportion of those participants’ listeners based on some demographic ( race, age, LSM profile, content of the station talk or music and, if music, the genre ), one should have regard to.
 Even when the respective economists reworked examples to concede some ground to their opponents case, conclusions to be derived from the data varied, as the data, predictably, was very sensitive to the exclusion and inclusion of certain participants, but less predictably, once modified HHI’s are taken into account also proved to be highly sensitive to assumptions about whether one is dealing with a full merger or a passive financial investment. This is because the formula for calculating the change in concentration (delta) varies, depending on which assumption is being made. Crudely expressed, the mathematics of modified HHI’s leads to lower deltas for passive financial investments than for a full merger assuming all else is equal.29
 We do not wish to burden this decision with all the permutations that were introduced in the course of proceedings, but we consider below two tables introduced at a late stage in the enquiry which serve to illustrate our point.
 We first consider the Commission’s Exhibit 32 that we alluded to earlier. This is selected as its represents the Commission’s refinement of its earlier work and one on which it relied during Dr Roberts’s testimony for its concentration thesis.30