Group Purchasing Organizations (GPOs) are well-known intermediary firms that play an important role in some supply chains. An important question that arises regarding GPOs is whether a GPO that benefits from group buying discounts always benefits Original Equipment Manufacturers (OEMs) under market competition. In other words, does the role of a GPO always result in a win-win outcome for OEMs and GPOs? In response, a bargaining framework has been used to investigate the procurement strategies of competing OEMs. The incorporation of a GPO in a two-tier supply chain consisting of two competing OEMs with a common supplier that has a quantity discount menu is analyzed. The result shows that low-purchasing cost for GPOs may harm OEMs from a cost-benefit perspective. This unintuitive result can be explained by different impacts that a GPO has on the purchasing process. Although a GPO can enlarge the size of trade surplus, it has important in uence on the size of the slice of the pie (profit sharing). Moreover, the procurement strategy of an OEM in equilibrium depends on not only the bargaining power, but also the competing OEM. Interestingly, unlike a weak OEM, a strong one may not prefer procuring through GPO.

Discourse analysis examines the impacts of human, gender and cultural interactions and social values on discourse, and studies the way these relationships are presented in the text. Hence, in this article, which deals with the phenomenon of bargaining in an Iranian culture, Kermanshah, the approach of critical discourse analysis is used to study the discourse of bargaining regarding the mind control process of the audience. According to Foucault, power has a non-predetermined structure, hence because of its elusive nature, participants in a discourse can play different roles. This research data is gathered utilizing a questionnaire (164) and recording some conversations (850 minutes), in three different social class areas in Kermanshah. The analysis of the data shows that discourse participants use different linguistic mechanisms to reach their goals in bargaining, such as topicalization, short single sentences, exclamatory, imperative and interrogative structures, besides prosodic prominence strategies such as changes in stress, intonation and juncture which can end in shifts in the focus of the information structure of the sentences. However, simple words with ideological connotative meanings have the highest frequency. Moreover, according to the findings, three highlighted behavorial strategies frequent in bargaining include the usage of religious beliefs, having ethnic tradition biases, and stating economic, social, and class problems. The results indicate that the various roles pertaining to the bargaining participants – buyers and sellers-put bargaining in the category of reverse discourse, as Foucault calls it. The seller, in the power hierarchy, is the superordinate through the ownership position, while the buyer is the subordinate. However, in mind controlling, the buyer’ s attempt to control the seller secretly makes them the controller, the one who applies power in a bottom-up order. Given that it is impossible to control the seller's mind without persuading them or without changing their worldview, bargaining is categorized as a rhetorical task, and the buyer, in this discourse, is the rhetor.

Lack of balance in transaction power between contract parties leads to a relatively deep gap between them causing one party of the contract to be named as poor party and the other party as strong party. Inequality in dependency levels, knowledge and urgent conditions of poor party are among the factors that pave the way for lack of balance in power between poor and strong parties. Legal justice necessitates proper strategies to be presented to face with this kind of inequality. In Iran's Law, only some have reached from title of misuse of urgency to solution of duress transactions, annulment. Moreover, a number of theories have been proposed in developed countries like United States and England, and some of them have been proposed by Iranian lawyers, which, present strategies for annulment of imposed or unreasonable terms. However, this study aims to apply a strategy which, in addition to supporting the poor party, takes a step to maintain the principle of transaction necessity, so that trade boom and motivation for gaining knowledge and specialty will not be disappeared. Exploiting Transaction Imitation Theory will be efficient with regard to this aim.