According to the new economic geography theory, geographical distance affects the decisions of economic agents by influencing their transaction costs, which also leads to differences in the spatial distribution of economic activities (Krugman, 1994) [5]. As a result, listed companies will also focus on transaction expenses due to geographical distance when carrying out M&A. Studies have shown that due to the requirement for information collection and ongoing communication, listed firms seek to invest in places with lower information collection costs and transportation expenses (Giroud, 2013) [6].

Based on the above logic, studies have been conducted to explore the impact of geographical distance on enterprise M&A behavior. Ragozzino (2009) found that there is less information asymmetry between geographically proximate companies [3]. So, the acquirer company is better informed about the operations of the target company. As a result, listed companies are more likely to acquire companies that are closer to their locations (Kang and Kim, 2008) [2]. On the other hand, closer physical proximity makes supervision of subsidiary management by the parent business easier after M&A, resulting in more effective integration (Chakrabarti and Mitchell, 2013) [7]. Di Guardo et al. (2016) found through further research that greater geographical distance brings higher information asymmetry, which increases cultural differences as well as political differences. This has a significant negative impact on M&A [8]. The above literature review shows that transaction costs associated with geographical factors are important factors that economic agents consider when making M&A decisions. However, the existing literature has only explored the economic consequences of geographical distance and has paid less attention to the impact of human geography, such as transportation, on enterprise M&A behavior.

HSR is one of the most important infrastructure developments. Infrastructure developments profoundly affect business sustainability, for example, the Shanghai Hongqiao district effect proposed by Chopra et al. (2021) [9]. The transportation infrastructure has brought various economic agents closer together and modified the spatial structure between cities (Clark, 1998) [10]. HSR, as a product of transportation development, while solving the problem of rapid transportation of a large number of passengers, has affected the efficiency of transmission of information and other elements. As a result, the economic consequences of the opening of HSR have received wide attention from both academic and practical circles. The economic consequences of the opening of HSR have been studied in the literature from two aspects: regional economy and company decision-making.

Different studies have reached different conclusions regarding the impact of HSR opening on the regional economy. It has been proved that the opening of HSR lowers transportation costs, thus boosting regional economic growth and wage growth (Yin et al., 2015) [11], leading to an increase in regional income levels (Chen and Silva, 2013) [12]. Liang et al. (2020) concluded that the opening of HSR can promote the economic growth of underdeveloped regions, which is mainly achieved by pushing investment and optimizing the industrial structure, in addition to providing favorable conditions for the development of tertiary industries along the route [13]. Wang and Cai (2020) show that HSR opening in more developed cities boosts the innovation capability of the less developed cities around them greatly [14]. On the other hand, some studies suggest that the "siphon effect" created by the opening of HSR only benefits the development of central cities or large cities, which will have an impact on the interests of the surrounding areas and magnify regional disparities in development (Vickerman et al., 1999) [15]. Li et al. (2020) found that large cities get faster economic growth and higher resource allocation efficiency with the siphon effect due to the opening of HSR [16].

In terms of the impact of HSR on business decisions, studies have found that the opening of HSR reduces firm inventory levels by declining in transportation and communication cost, as well as agglomeration effect (Cui and Li, 2019) [17]. Furthermore, Yang et al. (2019) demonstrated that the opening of HSR can optimize the efficiency of resource allocation between core and surrounding cities, thereby positively affecting core city productivity while negatively affecting peripheral city productivity [18]. Duan et al. (2020) found that the opening of HSR improves transportation accessibility and thus significantly boosts venture capital investment mobility across cities [19].

According to the above literature review, existing studies generally agree that the opening of HSR can reduce the transaction costs associated with geographical distance and facilitate the production factor mobility, which has an impact on the regional economy and company decision-making. However, less research has focused on M&A as a critically important resource allocation strategy.

Enterprise M&A behaviors are important matters and important decisions that affect the interests of stakeholders. One of the main concerns in both theory and practice is what factors can have a substantial impact on enterprise M&A behavior. So far, studies have been conducted to investigate the factors that drive corporate M&A behavior, primarily in terms of external and internal factors.

About the external factors, studies have investigated the impact of national industrial policies (Barbieri et al., 2021) [20], enterprises’ political connection (Schweizer et al., 2019) [21] and product market competition (Lee et al., 2019) [22] on enterprise M&A behavior. Barbieri et al. (2021) suggested that enterprise M&A behavior may not just be related to strategic individual behaviors activated by firms, but also stimulated by governments as a tool to promote structural changes in the sectors’ market [20]. Schweizer et al. (2019) showed that executives with a political connection are more likely to complete cross-border M&A at the expense of shareholders [21]. Lee et al. (2019) found that in an emerging economy with less developed capital markets and insufficient investor protection, product market competition improves market efficiency for corporate control in an emerging economy, supporting the complementary hypothesis between product market competition and corporate takeover [22].

About the external factors, studies have investigated the impact of board networks (Renneboog and Zhao, 2014; Cai and Sevilir, 2012) [23,24] and executive incentive (Grinstein and Hribar, 2004; Zhao et al., 2016) [25,26] on enterprise M&A behavior. Renneboog and Zhao (2014) investigated the impact of social network on the corporate M&A process from the perspective of board networks, finding that friendly social contacts make the acquirer company more active in the M&A process and that the information gathering ability of directors and interlocking directors can improve the success rate of M&A while shortening the negotiation time [23]. In addition, Cai and Sevilir (2012) found that both transactions with a first-degree connection and a second-degree connection are able to generate higher revenues for the acquirer company, indicating that board connectedness plays important roles in M&A behavior and leads to greater value creation [24]. Based on an executive incentive perspective, Grinstein and Hribar (2004) showed that CEOs receive higher bonus incentives when M&A deals are larger, and this incentive makes CEOs put more effort into closing M&A agreements [25]. In addition, Zhao et al. (2016) explored the key factors that influence the performance of corporate M&A in state-owned enterprises and found that increasing executive compensation can significantly improve the post-merger profitability of state-owned enterprises [26].

The above literature review shows that studies have explored the factors influencing enterprise M&A behavior in terms of external factors such as national industrial policies, enterprises’ political connection and product market competition, as well as internal factors such as board networks and executive incentive. However, studies have ignored the impact of objective environment and its changes on the M&A behavior of listed companies. Due to China’s vast territory, geographical distance, and other objective circumstances, there are significant discrepancies in information transmission speed and factor circulation efficiency across listed companies in different locations. Therefore, this paper delves into the impact of the objective environmental changes triggered by the opening of HSR on enterprise M&A behavior.