Corporate restructuring is a study area of great interest for researchers of SM (Bergh et al., 2008; Bowman and Singh, 1993; Chang, 1996; Untiedt et al., 2012), organization (Bergh and Lawless, 1998; Sembenelli and Vannoni, 2000), finance (Alessandrini et al., 2008; Denis and Kruse, 2000; John and Ofek, 1995), economics (Richter, 1997), sociology (Ahmadjian and Robbins, 2005; Hirsch and De Soucey, 2006) and psychology (Harner, 1987), among the better known disciplines. This paper will focus mainly on SM. However, the fields of finance and organization will also be considered because they are the pioneering fields in the study of BPR and are closely related to strategy (Alexander et al., 1984; Bowman and Singh, 1993).

Research into corporate restructuring began in the mid-1970s (Tan and Yuan, 2003), but it was only in the 1990s that its interest increased considerably. Furrer et al. (2008) include corporate restructuring among the top 20 research topics in SM. Kang et al. (2010) have reported that the study of restructuring has increased since 2008 due to its extensive application in those business decisions made to tackle recent global financial crisis.

A brief literature review allows identifying certain key issues about the current state of BPR research. First, BPR strategy can be implemented on a voluntary or mandatory basis. Following an analysis of a company’s value destruction or a decrease in a diversified company’s benefits, managers may decide to implement a voluntary BPR strategy. Otherwise, external pressures may sometimes force managers to restructure with a view to protecting their own jobs, among other things (Chatterjee et al., 2003). In the first case, the process begins through the internal mechanisms of corporate governance, the product market itself or pressure from institutional investors (John et al., 1992; Robbie and Wright, 1995; Seward and Walsh, 1996). In the second case, the decision to restructure or not is triggered by external mechanisms such as takeovers or capital market threats that may affect the control of the firm (Bergh and Lawless, 1998; Florou, 2005).

Second, SM scholars usually base their research into four approaches (Bergh, 1998; Moschieri and Mair, 2008): agency theory, transaction cost theory, the resource-based theory and evolutionary theory. The first two theories have been used primarily for the study of divestments and over-diversification (Hoskisson et al., 1999; Moschieri and Mair, 2008). The resource-based theory currently prevails in SM research, being widely applied in strategy studies (Barney et al., 2011; Nandialath et al., 2014). Finally, the evolutionary approach covers firm adaptation through business entries and exits (e.g., segregation, mergers and acquisitions) in response to environmental changes (Chang, 1996; Meyer and Lieb-Doczy, 2003; Moschieri and Mair, 2008).

Third, the literature identifies three possible directions a firm may take by implementing a BPR strategy: a) refocusing, which is when the firm owns a core business with unique capabilities, so it decides to divest peripheral businesses and renew and concentrate its efforts on its existing core business (Chatterjee et al., 2003; Geroski and Gregg, 1994; Haynes et al., 2003); b) repositioning, when the firm identifies a new core business and decides to regroup its resources around the new business (Byerly et al., 2003; Chang, 1996), and c) firm liquidation, as the last option and occurs when it is impossible to identify a core business that generates more economic value than by selling all the company’s lines of business (Byerly et al., 2003; Sengupta and Faccio, 2011).

Fourth, the methods commonly used for BPR are: a) divestitures (including spin-offs and sell-offs), understood as the parent company’s reduction in or sale of assets, product lines, subsidiaries or business units (Lee and Madhavan, 2010; Moschieri and Mair, 2008; Villalonga and McGahan, 2005), and b) acquisitions and divestitures (including mergers and takeovers), where the firm not only divests but also merges, cooperates or acquires new lines of business in order to implement a new set-up in its field of activity (Bowman and Singh, 1993; Hoskisson and Johnson, 1992).

The final citing sample consists of 452 articles with a total of 20,898 literature references to 12,525 different documents, which means an average of 46 references per paper. It is noticeable that the number of BPR-related papers published is increasing. By dividing the citing sample into three stages we note the following: the first stage contains the first 20 papers on BPR that appeared between 1959 and 1987; the second stage has a total of 176 papers published in the 1989-2000 period, and the third stage contains 256 articles published between 2001 and 2012.

In the first stage, the BPR-related papers were not published over consecutive years. Things changed in the second and third stages, when there was indeed continuity. However, the number of years in each period coincides (12). The citing sample increases by almost 600% from the first to the second stage, while from the second to the third stage BPR research increases by 36%. This clearly indicates that interest in the study of BPR has grown over time. Furthermore, it should be noted that part of the second stage coincides with the period of highest growth in research into corporate restructuring (Furrer et al., 2008).

Table I presents the ten journals most cited by the citing sample -only journals are to be found among the most cited sources. The most cited book appears in 43^rd place in the ranking (Ravenscraft, 1987). This indicator makes a clear distinction between general strategy research and BPR research. The study by Ramos-Rodriguez and Ruiz-Navarro (2004) shows that the eleven most cited references in the field of strategy are books, with the first paper appearing down in twelfth place.

It may be deduced that the basic field of study in BPR is related to journals on finance (Journal of Financial Economics, and Journal of Finance), management (Strategic Management Journal, Academy of Management Journal, Academy of Management Review, Administrative Science Quarterly, Organization Science, and Journal of Management) and economics (American Economic Review, and Journal of Political Economy). Regarding the overall ranking, it is worth noting the importance of the first four journals, as each of them accounts for more than 3% of the papers cited. Among them are two on finance and two on management, both disciplines especially related to the field of SM (Furrer et al., 2008).

Another interesting result is that 37.6% of the citations received are to be found in just ten academic journals, all of them with a very high impact factor in the WoS within the categories of business, management and finance. In addition, the rest of the papers in the cited sample (62.4%) correspond to different journals that have been cited by less than 1% in the BPR-related literature; two-thirds of the papers in the intellectual structure have been published in less popular journals with different approaches, as happens in the study by Wallin (2012).

Table II shows the authors who have contributed the most to the research into BPR. We have identified 8,265 authors from 12,525 different literature references. The first column is the percentage of papers in the citing sample that cite at least one study by a particular author. This criterion is used to sort the authors in this table. This helps to establish an author’s greater or lesser degree of relevance within the overall citing sample.

The second column shows the number of citations that indicate the extent of an author’s influence. The differences between one and another can be explained by an author’s more or less mainstream or specialist approach. That is, an author with many citations, but especially focused on finance, may have many citations without being cited as much by other disciplines. The contributions made by authors with many citations and many papers citing them are more mainstream precisely because they are cited by a larger number of papers.

The third column is scientific production. An author with many papers can be cited on numerous occasions, but these citations are concentrated in fewer papers in the citing sample because each paper cites this author several times. The fourth column shows the field of study of the authors. We decided to divide the sample in three fields of study: SM, finance and economics based in the journal(s) where the authors published their work about BPR. Some of the major findings presented in this table are as follows. Michael C. Jensen tops the ranking in terms of both citations and scientific output. There is no doubt at all that Michael C. Jensen is the largest contributor to the building of the intellectual structure of BPR. His contribution is based primarily on agency theory, an approach that explains the potential conflicts of interest involved in whether or not to make the decision to restructure the business portfolio.

In the field of SM, and behind Michael C. Jensen, Robert E. Hoskisson records the largest number of items included in the cited sample. The author has 28 papers included in this sample. In contrast, Michael E. Porter has fewer references in the sample, 17 papers. However, within SM field, he is the author with the highest percentage of citations received; nearly 20% of the citing sample quotes him at least once. These two scholars would therefore be the referential authors in the field of strategy in the study of BPR. In the case of Michael E. Porter, this is because he receives a greater number of citations from the citing sample, despite having fewer papers in the cited sample. This finding agrees with the work by Ramos-Rodriguez and Ruiz-Navarro (2004), in which Michael E. Porter is the most influential author in the field of SM. In summary, Robert E. Hoskisson is the author who has produced the most papers, and Michael E. Porter is the most cited author for the building of the intellectual base of BPR.

Adopting a more financial approach, Michael C. Jensen, Andrei Shleifer, Larry H.P. Lang, Kose John, Steven N. Kaplan, Gailen L. Hite, and Eugene F. Fama are among the authors with the most influence in the construction of the intellectual base of BPR. The last author (Fama) is a Nobel laureate in Economics (2013), known for his work on portfolio theory and asset pricing. All authors have contributed, above all, through techniques for measuring firm assets and performance.

To complete the descriptive part of this paper, we list the 50 most influential papers in the study of BPR from 1959 through to 2012, dividing the total citations by the number of years since the article was published, as explained in the methodology section. It is noteworthy that 43 of the 50 most influential papers are among the 97 articles chosen as the cited sample. The seven papers that do not appear in the cited sample are the latest ones to have been published, being therefore excluded because they had a fewer number of total citations (Capron et al., 2001; Colak and Whited, 2007; Dittmar and Shivdasani, 2003; Graham et al., 2002; Maksimovic and Phillips, 2002; Schlingemann et al., 2002; Vijh, 2002). Table III shows the papers ordered by the number of annual citations.

It can be seen that out of 50 items, only three are published in book form (Hoskisson, 2004; Ravenscraft, 1987 and Porter, 1985). This differs from the research on SM, where the first eleven of the cited references are books, and the first paper appears only in twelfth place (Ramos-Rodríguez and Ruiz-Navarro, 2004). There are two possible explanations for this difference. First, BPR research is a much more specific and specialized field than the study of SM. Second, the time variable is important, as more and more knowledge is based on articles from scientific journals than from books.

A further aspect to note is that the first six papers that have collaborated in the construction of BPR literature belong to a financial or economic journal, according to the classification of WoS. Furthermore, of the 50 most cited papers, 31 are published in a journal on finance, 3 are published in a journal on economics, 14 are published in a journal on organization, management or SM, and two are published in book form. This confirms that economics, finance and management are the pioneering fields in the study of restructuring, and have significantly influenced the intellectual structure of the study of BPR (Sánchez-Riofrío et al., 2015).

Another finding is the major influence of the works whose main subfield is the method involved in restructuring. Twenty of the 50 papers are classified under this heading, with 11 addressing diversification and four dealing with the different theoretical approaches that have served as the basis for BPR literature. This confirms that before considering the matter of restructuring itself, the literature began by studying the mergers, divestitures and acquisitions upon which BPR strategy is founded.

An additional aspect to be highlighted concerns the two most cited authors: Michael C. Jensen in finance and economics journals, and Robert E. Hoskisson in SM journals. This result is partially consistent with table II above, which renders the previous results more reliable.

Finally, the three journals that have published 35 of the 50 most influential papers are as follows: Journal of Finance with 15 papers, Journal of Financial Economics with 13 papers and Strategic Management Journal with seven papers. As can be noted, these three especially outstanding journals coincide with the three foremost journals in Table I above. This means that not only have they published most of the articles (quantity) but also the ones of greatest influence. Furthermore, they are the journals that receive the most citations and which publish the papers that have had the biggest impact on the intellectual structure of research into BPR.

A factor analysis has been performed of the 97 most cited articles in order to identify the most important issues that inform the intellectual structure of BPR. For the analysis of proximity between the works with the greatest impact on the intellectual structure of BPR, the co-citation matrix (this matrix stems from co-citation analysis) is transformed into a correlation matrix, and a factor analysis is performed. Table IV presents the five factors (components) extracted (principal component analysis, varimax rotation) with eigen-values greater than one, which together account for 94% of the total variance. This is a very high percentage, which means that these five factors explain the sample without losing much information. The components are considered to have a clean factor structure when at least three variables have their greatest weight in it (Costello and Osborne, 2005).

Appendix A shows the factor score for the cited sample (see http://www.guerrasynavas.com/pdf/Riofrio-Guerras-Forcadell_2017_Appendix_A.pdf).

Each component may represent one or more subfields of the literature on BPR. Factor scores can be interpreted as the degree to which that specific work contributes to the research topic. Due to the overall size of the table, 97 items, only 65 papers with a factor score higher than 0.7 are shown in the five components, as recommended by White and McCain (1998).

Regarding the works with higher factor scores in the first component (explaining 35.61% of the total variance), 22 of the 25 items belong to the field of SM, and the remaining three references are books. The most important subfields in this factor are: a) corporate strategy (Hill and Hoskisson, 1987; Hitt et al., 1996; Hoskisson and Hitt, 1988; Hoskisson and Johnson, 1992; Lieberman and Montgomery, 1988; Porter, 1987; Shleifer and Vishny, 1991); b) diversification (Bergh and Holbein, 1997; Hoskisson, 1994; Markides, 1995; Palepu, 1985); c) corporate restructuring (Bethel and Liebeskind, 1993; Bowman and Singh, 1993; Gibbs, 1993; Hoskisson and Turk, 1990; Johnson et al., 1993); d) corporate refocusing (Johnson, 1996; Markides, 1992), and e) divestitures (Duhaime and Grant, 1984; Hoskisson et al., 1994; Montgomery et al., 1984; Ravenscraft, 1987).

In this same factor, the key theories used to study BPR from a strategic point of view are named: agency theory, the resource-based theory (Bergh, 1995) and transaction costs theory (Williamson, 1975; Williamson, 1985). It could be inferred that this factor groups the most developed subfields in SM, and they have provided the platform for the development of BPR literature. It is important to note that the subfield of corporate restructuring accounts for four of the seven papers in the special issue of SMJ (Vol. 14 Summer issue, 1993), with very high factor scores, which confirms the importance of this special issue for the advancement of BPR.

Two major aspects stand out in the second factor. First, there are works with a positive sign and higher factor scores referring to different ways of restructuring. Second, with a negative sign, there are works based on the resource-based theory and organizational theory. It is important to mention that all the works with a positive sign, with the exception of one that is a book, appear in the Journal of Finance or in the Journal of Financial Economics. Moreover, all the papers with a negative sign, except for one that is a book, appear in journals in the field of management or strategic management (Bowman et al., 1990; Eisenhardt, 1989). In this case, the positive and negative signs only differentiate articles with a financial perspective from papers with a management perspective.

The following works are found on the topic of “restructuring methods”: Hite and Owers (1983), Miles and Rosenfeld (1983), Schipper and Smith (1983), Cusatis et al. (1993), Daley et al. (1997), and Krishnaswami and Subramaniam (1999) on the subject on spin-offs; Schipper and Smith (1986) and Slovin et al. (1995) on equity carve-outs; Alexander et al. (1984), Jain (1985), and Hite et al. (1987) on sell-offs; Mulherin and Boone (2000) on acquisitions; Rosenfeld (1984), Klein (1986), Boot (1992), John and Ofek (1995), and Lang et al. (1995) on divestitures.

It should be noted that although the first factor also contains works on divestitures, in this second factor the subfield is studied from a financial perspective. The works on the resource-based theory are: Penrose (1959), Wernerfelt (1984), Prahalad and Hamel (1990), Barney (1991), and Teece (1997). Furthermore, there is a paper on the organizational approach (Dimaggio and Powell, 1983). It is worth mentioning that, albeit with lower factor scores, there are two works (Comment and Jarrell, 1995; Porter, 1985) related to a company’s outcomes; specifically dealing with share performance and competitive advantage. The explained variance is 32.65% in this latter factor.

The third factor has an explained variance of 15.31%, and is mostly related (8 out of 11 references) to the subfield of corporate governance. The works by Amihud and Lev (1981), Weisbach (1988), Morck et al. (1988), Kaplan (1989), and Jensen and Murphy (1990) address management teams/board of directors, while the works by Berle and Means (1932), Jensen and Meckling (1976), Jensen (1989), and Lehn and Poulsen (1989) analyze the ownership structure. The literature considers that a takeover bid is the external control mechanism for managers to sit up and refocus their strategy in order to ensure their company’s survival (Chatterjee et al., 2003). The works by Roll (1986), and Bhagat et al. (1990), with lower factor scores, are based on takeovers as an additional subfield in this factor.

The fourth factor is related to a single work with an explained variance of 7.43% and a factor score of 0.762 (Lins and Servaes, 1999). This fourth factor contains a paper that analyzes the matter from a financial perspective in different institutional environments, that is, internationalization. Although a part of the first factor also examines diversification, it does it in the context of the field of SM and relates it to restructuring.

Finally, the fifth factor contains a work with a factor loading of 0.731 and an explained variance of 3.48% of the total (Jensen and Ruback, 1983). This work, closely related to those on corporate governance, is a comprehensive review of the scientific literature on corporate control and concludes that the control market is a platform in which management teams compete for the right to manage corporate resources. Several studies suggest that corporate control is an important determinant in the decision on whether or not to implement a strategy, not only in terms of BPR but also as regards corporate restructuring (Denis and Kruse, 2000; Haynes et al., 2003; Hoskisson et al., 2005; Inoue et al., 2008). Table V provides an overview of the subfields with higher factor scores in each component.

Some observations are pertinent regarding the data obtained from this factor analysis. Identifying the intellectual structure through bibliometric techniques and factor analysis allows us to examine the basic conceptual foundations of BPR with a view to consolidating the theoretical contributions and detecting the starting point for research into this topic. Furthermore, it is noted that the fields of management, economics and finance are the ones that have initially contributed the most to the intellectual base of BPR literature. Concepts such as divestiture and diversification have been widely studied in both financial and strategic literature, often coinciding on certain aspects, such as the definition of both concepts, but also contributing from their own perspectives. For example, most scholars in the field of SM consider divestiture to be a subfield of the restructuring strategy (Bowman and Singh, 1993; Hoskisson et al., 1994), while for many financial scholars divestiture may be considered a strategy in itself for improving firm performance (Boot, 1992; Lang et al., 1995).

The factor analysis of the second component mentions two works (Comment and Jarrell, 1995; Porter, 1985), which record lower factor scores for a firm’s performance or results. However, the majority of the 97 papers reviewed here with the exception of the items on theories, corporate governance and corporate control, bear some relation to firm performance. Therefore, both the works on finance and economics and those on organization and SM seek to use restructuring to improve shareholder wealth and firm performance.

It is interesting to compare the subfields identified by this article’s factor analysis with those forthcoming from the same analysis conducted by Sanchez-Riofrio et al. (2015). An initial reading reveals three clearly overlapping areas in both studies: divestitures, corporate governance, and corporate control. However, these areas are complemented by others, and are grouped differently, due mainly to the papers’ different goals and their analysis of different samples (cited and citing sample).

The subfields identified in the cited sample (this article) represent the topics studied as antecedents of BPR research in Sanchez-Riofrio et al. (2015). Before studying BPR strategy, academics extensively investigated divestitures, acquisitions, corporate governance, diversification, and corporate control, without such studies necessarily having a BPR perspective. These topics constituted the basis for subsequent research focusing on BPR. This confirms that the most significant factor is Strategic Management, as a particularly important area in this field, especially regarding business diversification, whose excessive levels may inform the need for a BPR strategy.

Meanwhile, the three subfields identified in the citing sample (Sanchez-Riofrio et al., 2015) are directly related to the dedicated research on BPR. Divestiture is studied as a restructuring method. In fact, the concept of BPR implies that a company has to undertake at least one significant divestment. In addition, BPR academics consider corporate governance and corporate control refer to the mechanisms, both internal (boards, ownership structure) and external (based on markets), shareholders have for controlling managers’ discretionary behavior forcing them to apply a BPR strategy. Economic performance refers to the results sought by those shareholders supporting a BPR strategy.