Nowadays, business environment is becoming increasingly competitive, which is a negative factor that affects business survival (Tsitmideli et al., 2016 & 2017). Businesses should find new ways for creating a sustainable competitive advantage in order to be able to survive and develop (Skordoulis et al., 2017). For the last forty years, there has been a growing body of research on the antecedents for predicting the performance of M&A, but the key factors that can guarantee the success or failure of a merger remain unknown. Mergers and acquisitions have been a famous strategy for companies in order to achieve a corporate growth and diversification, especially by creating synergies (Antoniadis et al., 2014; Martynova & Rennenborg, 2006; Stahl, 2003; Stahl & Voigt, 2003) and have a very important role for all over the world (Selcuk-Akben, 2015). Mergers and acquisitions became an important issue and many researchers have focused on predicting the performance of companies after an M&A. Many firms have no alternative but to merge, acquire or be acquired (Bruner, 2011). Until now, businesses have two choices: grow or die. Mergers and acquisitions in recent times are very different. Today, merger or acquisition is quite strategic and operational in nature (Galpin et al., 2010). Koumanakos et al. (2005) noted that the basic reason for companies making this decision is the prospects of growth because the merged companies can offer more benefits for the shareholders compared to individual companies. The purpose of this research is to evaluate employees' reactions and the impact of the new corporate culture within the M&A integration process. It is also necessary for the new company to adopt a new culture, where all employees will learn, follow and respect. To sum up, there are several factors that may affect the failure of an M&A. This study is focused on the impact of M&A on corporate culture after a merger or acquisition with the following main question: Which is the most important factor that will cause a merger both for Aegean and Olympic Air employees? In this research, the degree of employees' resistance to change in Aegean and Olympic Air will be examined, as well as the difference between these two different corporate cultures and the possibility of the two cultures that merged smoothly at the pace of these companies.
Mergers and Acquisitions
A merger is defined as a strategy that combining two companies and occurs when two businesses join or merge to one single company with a new name. As Coffey et al. (2002) perceptively state, M&A represent a "marriage". Machiraju (2007) has stated that merge take place when two companies differ significantly in size. "Acquisition refers to a situation where one company acquires another and the latter ceases to exist" (Machiraju, 2007). To sum up, a merger "creates" a new company with a new name from two organizations who join forces. An acquisition happens when one business buys another company which is smaller and might be absorbed within the parent organization or run as a subsidiary (Taneja & Saxena, 2014).
The Causes of Mergers and Acquisitions
Many studies highlight some of the basic reasons why companies use mergers and acquisitions. Mergers and acquisitions are also used for risk spreading or for saving a business (Chalikias et al., 2016). Many mergers and acquisitions carry out when management of any business recognizes the need of a new corporate identity (Sherman et al., 2006). Many mergers and acquisitions carry out for market dominance and reaching economies of scale (Schuler et al., 2001). Acquisitions are undertaken to achieve vertical and horizontal operational synergies (Sherman, 2010). There are several primary rationales that determine the nature of a proposed merger or acquisition. These rationales are (Roberts et al., 2010): Strategic, Speculative, Management failure, financial necessity and Political rationale.
Corporate Culture and Resistance to Change Model
One of the biggest challenges that faced by managers in post-M&A is the examination of factors that affect organizational identification in the new company from the aspects of organizational factors of justice and culture (Ismail & Baki, 2017). Several authors have attempted to define corporate culture. Kreps (1990) defined corporate culture as "a coordination mechanism in situations with multiple equilibrium and it is also a way to deal with unforeseen contingencies" (Bouwman, 2013). Cremer (1993) argued that corporate culture is "the portion of specific human capital that is shared by many employees of the firm". Lazear (1995) states that corporate culture is shared beliefs or preferences that arise from an evolutionary process. The key benefit of culture is that it acts as a substitute for explicit communication by providing a common language, a shared knowledge of relevant facts a shared knowledge of key behavioral rules (Thakor, 2016). Hermalin (2001) uses an industrial organization (IO) for corporate culture, which he assumes to be a technology that affects costs. Cameron & Quinn (1999) indicated that even a highly successful company has a distinctive, easily recognizable corporate culture. A variety of surveys have shown over the years that corporate culture matters for M&A performance. It is also important to be referred that cultural differences in the M&A decision-making process is neglected (Weber & Tarba, 2012). A report by Aon Hewitt (2011) presents the results of a survey of 123 firms worldwide from a variety of industries. More specifically, 50% of the respondents answered that M&A in their companies failed to satisfy their expectations. The top three reasons that led to unsuccessful cultural integration were: a lack of top management agreement on the desired culture (48%), culture risks not recognized during the due diligence phase (48%) and a lack of top management support (44%). Fiordelisi & Martelli (2011) examine how corporate culture affects M&A success in banking. One of the biggest findings of their research is that cultural homogeneity (the acquirer and target have similar cultures) is not significantly related to merger success. Rather, certain types of cultural heterogeneity between the acquirer and target help predict success. These results showed that while cultural alignment reduces conflicts after the merger, it doesn't imply synergies. On the contrary, some cultural differences can imply the existence of such potential synergies. According to Mielly et al. (2016), Deloitte point out that cultural impact is responsible at 30% for M&A mismatches, Bain states that this factor is the most effective factor for M&A failures and the Hay group believes that the combination of corporate cultures and structures affects the 90% of M&A's failure to achieve their goals.
Issues and Challenges of Mergers & Acquisitions
Merge is most of the time a management decision. Weber (2015) maintains that the most important factor of failure in mergers and acquisitions is that there is no provision for the human factor during this process. Sometimes employees have to accept it and have little participation. If an M&A takes place, this fact means that two different companies or organizations have to cooperate and employees have to work together. An M&A brings on many changes will uncertainty (Davy et al., 1988). According to Scott & Jaffe (1988), the biggest challenge comes after the merger or change of workplace. A change is a fact and its acceptance requires much more energy and effort than many managers probably think. Bhansing (2010) states that managers often focused on the technical aspects of a change, while they don't give importance on the human side of the change like guiding and supporting the employees during a process (Demers et al., 1996). Human resource issues can reduce mistakes that are made during an M&A process (Schuler & Jackson, 2001).
The following hypothesis of this research is described below:
[H.sub.1]: The most important factors which will cause a merger both for Aegean and Olympic Air employees is to achieve vertical and horizontal synergies, the spread of risk and the need for market dominance and...