Does Business Model Innovation Enhance the Sustainable Development of New Ventures? Understanding an Inverted-U Relationship

Improving the sustainable development of new ventures and helping them survive and develop in the entrepreneurial environment are important research issues. Business model innovation is considered as a potential way for new ventures to enhance their sustainable development capability and performance. Although previous studies have pointed out that there is a positive linear relationship between business model innovation and sustainable development, little research has found the nonlinear relationship between them, as well as the moderating effects of competitive strategy innovation and strategy flexibility. In this study, an empirical model was established to test our hypotheses and answer our research questions. Analysis of data collected from 326 questionnaires shows that an inverted-U relationship exists between business model innovation and sustainable development such that new ventures with low or high business model innovation have worse sustainable development than new ventures with appropriate business model innovation. Moreover, this paper finds that competitive strategy innovation and strategic flexibility positively moderate the inverted-U relationship between business model innovation and sustainable development of new ventures. From a theoretical perspective, this study offers a model with which to understand the impacts of business model innovation, and contributes significantly to the research on new ven- tures. From a practical perspective, this paper provides new insights into the management of new ventures and recommends several practical strategies for managers and practitioners.


Introduction
New ventures have become a popular field of study in the business management literature [1]. The world is presently undergoing an important stage of economic restructuring in which enterprises are required to change their capacities and adapt to policy and environmental changes. Previous studies [2] have found that the failure of new ventures is mainly from risk-taking and market changes. Improving sustainable development of new ventures in the entrepreneurial environment has become an important research issue.
The sustainable development of enterprises refers to the process of continuously pursuing the business objectives and ensuring the core competitiveness of enterprises [3][4][5]. New ventures should not only ensure that they have continuous profitability in professional fields, but also have sustainable competitive advantages and sustainable innovations [6].
The key to maintain the sustainable development of a new venture is to ensure the stability and rationality of its various financial and innovation indicators, that is, the new venture should rely on stable investment income, reliable solvency, strong profitability, excellent operation capability, reasonable capital structure and sustainable innovation to ensure the sustainable development performance [7].
Business model innovation is considered to be the key to enterprise development and independent innovation [8][9][10]. Previous studies have pointed out that business model innovation is more important than technology and service innovation [11]. In our society, the competition of enterprises is not only about technology, products and services, but also about the business model [12]. If separated from the effective business model, the enterprise may lose the foundation of sustainable development and income generation. Therefore, business model innovation is the higher level of innovation content [13,14]. Especially for new ventures, promoting business model innovation is helpful for them to adapt to the current environment and enhance sustainable development capability. Previous studies have found that business model innovation is positively associated with the sustainable development of enterprises. However, business model innovation will also bring certain risks to enterprises [15], and then reduce their sustainable development. Many studies have pointed out that excessive business model innovation may not be accepted by the market and stakeholders [16,17], resulting in market risks and financial risks. Moreover, business model innovation may also be imitated by other competitors [18,19], thus weakening the competitive advantage and reducing sustainable development of enterprises. Therefore, new ventures with low or high business model innovation could have worse sustainable development than new ventures with appropriate business model innovation.
Due to the complexity of the current market and entrepreneurial environment, the previous positive correlation may no longer be applicable to the current new ventures. Based on the above analysis, this paper considers that the relationship between business model innovation and sustainable development capability may not be a linear relationship but a curve relationship. Although the relationship between business model innovation and sustainable development capability is curvilinear, whether the shape of the curve is inverted U-shaped or S-shaped still needs further discussion. Inverted U-shaped relationship means that certain business model innovation can improve the sustainable development capability of new ventures, but after reaching the peak, the role of business model innovation will negatively affect the sustainable development capability. S-shaped relationship means that both low and high business model innovation will enhance the sustainable development capability of new ventures, but medium business model innovation will reduce the sustainable development capability of new ventures. This paper considers that the inverted U-shaped relationship is more likely to exist in new ventures. The business model innovation can positively affect the level of sustainable development performance to a certain extent. However, excessive business model innovation must invest a lot of funds and resources, which makes new ventures face greater risks and uncertainties, and then reduces their sustainable development capability. Hence, low or high business model innovations have worse sustainable development performance than new ventures with appropriate business model innovation, i.e., an inverted-U relationship exists between business model innovation and sustainable development performance. Although a large number of studies have explored the linear relationship between business model innovation and sustainable development [20,21], few have explored the curve relationship between them. To better understand the role of business model innovation in new ventures, more studies need to be done. Therefore, this paper mainly explores the inverted U-shaped relationship between business model innovation and sustainable development capability of new ventures.
Moreover, competitive strategic innovation can effectively help new ventures to gain advantages in competition, and then promote their survival and development [22]. The innovation of competitive strategy is the premise of the development and growth of new ventures, and also one of the main ways to reduce market risks and improve competitive advantages [23]. Competitive strategy innovation is to gain competitive advantages through the planning of enterprise behavior, and competitive advantage comes from some links of enterprise value chain [24,25]. These links can create unique, irreplaceable and non-imitative value. It can be seen that the essence of competitive strategy innovation is to win competitive advantage for new ventures through strategic planning in line with the Sustainability 2021, 13, 262 3 of 19 above three characteristics. Therefore, competitive strategy innovation of new ventures could reduce market risks and positively affect the relationship between business model innovation and sustainable development.
Furthermore, the latest research shows that the recombination of resources is the key to create and obtain sustainable value [26]. New ventures need to transform the matching resource base while carrying out business model innovation [27]. Strategic flexibility can help new ventures dynamically adjust internal and external resources and capabilities, and realize the matching of resources and innovation [28]. If the enterprise fails to establish the core resources and capabilities matching with the innovation scheme, it is still unable to block the imitation of competitors; thus, it is difficult to improve their sustainable development [29]. In the practice of innovation, many new ventures fail because they cannot establish the resource system matching the innovation scheme. Therefore, the innovation plan needs new ventures to have the strategic flexibility to reallocate resources. Strategic flexibility is the capability of an enterprise to cope with uncertain environment by accumulating flexible resources and coordinating resource combinations [28]. Strategic flexibility is an important factor for new ventures and may moderate the relationship between business model innovation and sustainable development.
The purpose of this paper is to examine the potential relationship between business model innovation and the sustainable development of new ventures, as well as the moderating effects of competitive strategy innovation and strategic flexibility. This paper attempts to answer the following research questions: Research Question 1: Is there an inverted-U relationship between business model innovation and the sustainable development of new ventures?
Research Question 2: What is the moderating effect of competitive strategy innovation and strategic flexibility on relationship between business model innovation and sustainable development?

Business Model Innovation
An enterprise's business model refers to its operational and profit-making strategies, value creation processes, and technological and economic transformation [8,30]. Business model innovation encompasses various connotations and structural elements and is recognized as an important means of promoting the development and core competitiveness of enterprises [11]. Generally, a business model contains many elements. The innovation of a business model must contain at least one element, which is obviously different from other enterprises [12]. Business model innovation specifically refers to enterprises providing new products and services, creating new industrial fields or providing existing products or services in an unprecedented way [13,14]. For example, there are countless business model innovations in Internet thinking, such as the sharing economy model represented by Uber and Airbnb, the Internet direct sales model initiated by WarBy Parker and the social commerce based on customer interaction. Low business model innovation means that the difference between the business model of an enterprise and other similar enterprises is weak, and the products, services or marketing methods provided by the enterprise are similar to those of its competitors. High business model innovation means that there is a big difference between the business model of an enterprise and other similar enterprises.
Business model innovation can help new ventures obtain effective resources, improve their market efficiency and explore new markets in which to create higher value [12]. Previous studies indicate that business model innovation offers new ventures a new method and logic to gradually acquire value based on their original business models [11]. Business model innovation is also an innovative way for new ventures to recreate their business models based on their customers, technology, equipment and the economy. Depending on the process, business model innovation can be divided into four categories: full innovation, partial innovation, expansion innovation, and realization innovation [13,14]. Previous studies have mainly focused on the components of business models [31], the creation and transformation of business models [14], and the effects of the business model on capability [11]. Business model innovation can help new ventures reintegrate their internal and external resources [13,14]. Business model innovation can improve the operations of new ventures with respect to novelty and efficiency, helping them respond to market demand and enhancing their core competitiveness, in turn affecting their sustainable development.
However, many studies have also pointed out that excessive business model innovation may bring risks to enterprises, thereby reducing their performance and sustainable development [15]. Although many business model innovations bring certain competitive advantages to enterprises, these innovative business models do not conform to the industry rules and eventually lead to failure [9]. Excessive business model innovation may face the risk of not being accepted by the market and stakeholders [17]. Excessive business model innovation means that the value creation methods adopted by enterprises are completely different from other enterprises. Due to the lack of understanding of customer demand and the product itself, many business model innovations failed to get enough customer recognition [19]. For example, Motorola's iridium project is a failure of business model innovation. Iridium allows users to make phone calls from anywhere in the world. However, this kind of business model innovation failed because it was not accepted by users and the market. Therefore, any business model innovation must be tested by the market. Moreover, excessive business model innovation can bring capital risk to enterprises. Enterprises must maintain the continuous operation of funds in the process of operation [32]. In the early stage of implementing business model innovation, due to the lack of effective income sources and sufficient customer groups, the capital chain may break, leading to the enterprise falling into crisis [19]. Entrepreneurial failure is inseparable from market positioning, capital problems, team problems, product problems, operational problems and external factors. However, in these failed companies, the most prominent reason is the break of capital chain caused by business model innovation. In addition, industry environment may also make business model innovation reduce the performance and sustainable development ability of enterprises [32]. Industry environment may also make business model innovation reduce the performance and sustainable development of enterprises. For example, the change of policy will lead to the loss of business model advantages. Therefore, business model innovation can not only bring positive impact to enterprises, but also have certain risks and negative effects.
Based on what was discussed above, this paper considers that an inverted-U relationship exists between business model innovation and sustainable development, i.e., low or high business model innovations have worse sustainable development performance than new ventures with appropriate business model innovation. Although the business model innovation positively affects the level of sustainable development performance to a certain extent, its effect decreases as the level of business model innovation increases. This paper proposes the following hypothesis: Hypothesis 1 (H1). An inverted-U relationship exists between business model innovation and sustainable development performance such that new ventures with low or high business model innovation have worse sustainable development performance than new ventures with appropriate business model innovation.

Competitive Strategy Innovation
Competitive strategy innovation is the expansion of innovative thinking at the strategic level and arises from the integration of enterprise innovation and strategic decisionmaking [22,33]. Competitive strategy innovation refers to the ways in which enterprises move beyond traditional competitive strategies and develop innovative strategies such as differentiated marketing, unique resource integration and personalized customer service to gain advantages in the industry [34]. The core problem of enterprise competitive strategy is how to establish and maintain the specific position of enterprise products in the market by determining the relationship among customer demand, competitor products and enterprise products [23]. The most common competitive strategy innovation includes three aspects [35,36], as follows. The first strategy is to strive to reduce costs, reduce prices and maintain competitive advantage. The second strategy is to provide unique products and services. The last strategy is to focus on a specific customer group, a segment of a product series or a regional market. In order to defeat competitors, enterprises can take price war, function war, advertising war, promotion war, service war, category war to establish their own competitive advantage.
Competitive strategy innovation can effectively help new ventures gain a competitive advantage, increasing their chances of survival and promoting their development [23]. Competitive strategy is an important dimension of innovation and is the foundation of enterprise growth and development [35]. Competitive strategy innovation emphasizes the formulation of appropriate innovative competitive strategies to meet market demand and adapt to developmental needs [24]. Only by going beyond traditional competitive strategies can enterprises meet and overcome challenges. In addition, competitive strategy innovation may help enterprises cooperate with each other, integrate their resources and refine the market to ultimately improve their operational performance and capability.
Through the reshaping of market competition, competitive strategy innovation can help meet the needs of potential customers. However, it is difficult for new ventures to reshape existing market conditions [36]. Rational new ventures typically form alliances with other enterprises both inside and outside of the industry and can, in cooperation, disrupt the existing competitive market. Thus, new competitive strategies are often accompanied by open rather than closed innovation. By mobilizing stakeholders and even their competitors, new ventures can jointly reshape competitive patterns, divide the market share and achieve mutually beneficial results. This kind of open cooperation and competition is more conducive to new ventures in terms of sustainable development of new ventures. Therefore, this paper proposes the following hypothesis:

Hypothesis 2 (H2). Competitive strategy innovation positively influences the sustainable development of new ventures.
Previous studies have pointed out that business model and competitive strategy are different. The main difference between them is that business model is oriented by value creation [37], while competitive strategy is oriented by establishing competitive advantage [35]. However, it can be seen from the progressive process of the concept of business mode that the two orientations should be interdependent and indivisible. The purpose of business model and competitive strategy are the same. From the perspective of value activities before implementation, they are the planning or design of value creation activities that can obtain competitive advantages [38]. From the perspective of implementation, they become the description of value creation activities that bring competitive advantages [39].
Competitive strategy innovation could positively moderate the inverted-U relationship between business model innovation and sustainable development. Business model innovation is the improvement of enterprises' internal integration and value creation [40], while competitive strategy innovation is the solution for enterprises to cope with external environment and competitors [38]. These two kinds of innovations promote the sustainable development of new ventures from the internal and external aspects, respectively. Moreover, the two kinds of innovation are mutual influence and coordination. For example, in the process of their own business model innovation, new ventures also need competitive strategy innovation to cope with external competition, so as to establish core advantages. Competitive strategy innovation can strengthen the positive effects of business model innovation and weaken the negative effects of business model innovation on sustainable development of new ventures, which leads to enhance the inverted-U relationship. Based on what was discussed above, we hypothesized:

Hypothesis 3 (H3).
Competitive strategy innovation positively moderates the inverted-U relationship between business model innovation and sustainable development.

Strategic Flexibility
Strategic flexibility means that enterprises can achieve their goals more effectively [41]. In the dynamic environment, enterprises can actively adapt to changes, use changes and manufacturing changes to improve their competitiveness and formulate optional action rules and corresponding programs [42]. The strategic thinking capability of the top leaders is the key factor to determine the strategic flexibility of enterprises [43]. The capability of strategic thinking is different from the general capability of observing, analyzing and dealing with problems [28]. Strategic flexibility requires the managers to understand the changes of the external environment and internal situation of the enterprise in time, analyze and judge the trend of its development and the influence on the growth of the company and actively focus on the thinking of long-term impact [41]. In particular, when considering the advantages of the enterprise, leaders should imagine how to maintain the existing advantages [42]. When the company has no advantages, leaders should conceive how to establish the future advantages through certain ways and means. These are the basic premise to make enterprise strategy flexible.
Moreover, the correct decision-making of enterprise leaders requires all employees to implement actively and creatively [28]. First of all, all members need to respond in terms of ideas and positive psychological emotions. Without this positive response, the sustainable development of enterprises is unlikely. Secondly, the executive ability of an enterprise depends not only on the working ability of each member, but also on the coordination capability within the enterprise. There may be some contradictions and conflicts among various departments of the enterprise, because each has certain goals, which are unlikely to be consistent with the overall objectives of the enterprise at any time.
Strategic flexibility can help enterprises dynamically reconstruct resource base to achieve strategic transformation [41], which has an important impact on the realization of business model innovation [42,43]. Strategic flexibility is divided into resource flexibility and coordination flexibility [28]. According to the research of strategic flexibility, whether an enterprise can dynamically restructure resources depends on the flexibility characteristics of resources and the coordination flexibility shown by the organizational process of using resources. Resource flexibility depends on the use scope of existing resources, the cost of resource use conversion and the time required for resource use conversion [44]. The more extensive the use of resources, the lower the cost of use conversion, and the faster the speed, the higher the resource flexibility of enterprises. The higher the flexibility of existing resources, the larger the scope of enterprise selection, the more conducive to the rapid reintegration of resources [45]. Coordination flexibility is the ability of an enterprise to reorganize internal and external resources and establish a new resource chain to adapt to environmental uncertainty [46]. Flexible organizational system can provide space for enterprises to reorganize new resources. In the enterprises with low coordination flexibility, the organizational process system is more rigid, and it is difficult to identify all the new resource combinations that do not conform to the original conventions, and it is difficult to obtain organizational support for new resource integration [28]. The high coordination flexibility of enterprise organization process is more flexible, which can help enterprises identify the use range of resources, establish and allocate new resource combination [47]. Coordination flexibility is more conducive to the large-scale integration and allocation of internal and external resources in dynamic environment. Therefore, strategic flexibility from the perspectives of resource and coordination can enhance sustainable development of new ventures. Based on what was discussed above, we hypothesized: Resources are the basis of business model innovation [43]. As any activity needs resources, the current process of business model innovation must be supported by resource combination [28,48]. Therefore, whether to build a matching resource mechanism is the key to whether business model innovation can ultimately create value. Previous studies from the perspective of value capture show that although business model design can improve the capability of enterprise value creation and acquisition, the potential of business model design can only be realized by building matching resources [43]. When enterprises have certain resources, business model innovation can help them to improve sustainable development.
Strategic flexibility can help new ventures achieve better performance in the process of implementing business model innovation, and then enhance their sustainable development. New ventures with high strategic flexibility have stronger capability of resource integration and resource coordination than new ventures with low strategic flexibility. Then, high strategic flexibility could enhance the relationship between business model innovation and sustainable development. On the contrary, low strategic flexibility may reduce the impact of detailed business model innovation on the sustainable development, because new ventures cannot effectively use and integrate internal and external resources. Therefore, strategic flexibility could moderate the relationship between business model innovation and sustainable development, i.e., strategic flexibility can enhance the positive effects of business model innovation and diminish the negative effects of business model innovation on sustainable development, which leads to improve the inverted-U relationship. Based on what was discussed above, we hypothesized:

Data Collection
To test our hypotheses, data were collected using a questionnaire survey. Based on a research project by Guangzhou Rural Commercial Bank (3 January 2020 to 22 January 2020), the questionnaire was issued to small and medium-sized new ventures in Guangzhou. The process of data collection was divided into three stages. The first stage involved scale selection and questionnaire design. The construct measurements were borrowed from the literature but with minor improvements and transformations to suit the specifics of the present study. Strict translation methods and execution steps were adopted for the scale. The second stage involved a preliminary survey. Executives from 15 new ventures were interviewed to determine whether the questionnaire was appropriate to answer the research questions. The questionnaire was then modified according to respondent feedback to obtain the final questionnaire. The third stage involved the study itself. According to Guangzhou Rural Commercial Bank's customer return visit project, 400 small and me-

Data Collection
To test our hypotheses, data were collected using a questionnaire survey. Based on a research project by Guangzhou Rural Commercial Bank (3 January 2020 to 22 January 2020), the questionnaire was issued to small and medium-sized new ventures in Guangzhou. The process of data collection was divided into three stages. The first stage involved scale selection and questionnaire design. The construct measurements were borrowed from the literature but with minor improvements and transformations to suit the specifics of the present study. Strict translation methods and execution steps were adopted for the scale. The second stage involved a preliminary survey. Executives from 15 new ventures were interviewed to determine whether the questionnaire was appropriate to answer the research questions. The questionnaire was then modified according to respondent feedback to obtain the final questionnaire. The third stage involved the study itself. According to Guangzhou Rural Commercial Bank's customer return visit project, 400 small and mediumsized entrepreneurship-oriented enterprises from Guangdong Province of China were selected to participate. These research objects are entrepreneurial enterprises, including agriculture, manufacturing and service industries, such as green farms, textile companies, property management, catering companies, paper products, clothing manufacturing, household appliances manufacturing, intelligent products, IT software design, machinery manufacturing, material manufacturing, furniture design, food processing and other different types of enterprises. These research objects basically cover most common types of enterprises and satisfy our research needs. Questionnaires were independently completed by two managers or chief executive officers from each enterprise. In total, 335 questionnaires were collected, representing a recovery rate of 83.75%. After the elimination of invalid questionnaires and those with missing items, 326 valid questionnaires remained.

Variable Measurement
Based on the relevant literature, the feedback results of the preliminary survey, and the real-world situation of new ventures in China, questionnaire items were adjusted to ensure the reliability and validity of measurement constructs. All questionnaire items were based on a 5-point Likert scale (5 = strongly agree and 1 = strongly disagree).
The measurement of business model innovation was based on research by Zott et al. [49] and included five items. The measurement of competitive strategy innovation was based on research by Markides [50] and included three items. Based on a study by Sanchez [28], strategy flexibility was measured using 11 items encompassing the dimensions of resource flexibility and coordination flexibility. The measurement of sustainable development performance was based on research by Kostopoulos et al. [51] and involved the dimensions of financial performance and innovation performance (9 items). Year, scale, type, high-technology and sales were included as control variables in the research model. Year is based on the time of establishment of the enterprise. The older an enterprise, the better its abilities and potential for business model innovation. Size refers to the total number of employees. Larger enterprises have the ability to integrate a greater number of resources, which is conducive to innovation. Type refers to the industry in which the enterprise is located. High-technology refers whether an enterprise belongs to a high-tech industry. Sales volume is the profit growth of enterprises in recent years. Table 1 shows the sample characteristics of this study. Table 2 shows research constructs and measurements.

Reliability and Validity of Measurements
The reliability and validity of the measurements were assessed. The KMO value was greater than 0.75 for all variables, and Bartlett's test of sphericity for each variable was significant, indicating correlation between variables. Table 3 shows the factor loadings, Cronbach's alpha and average variance extracted values for specific constructs. Average variance extracted values ranged from 0.882 to 0.929, and Cronbach's alpha coefficients for all variables were greater than 0.897, indicating reliability of the scale. To ensure the validity of the questionnaire, scale items were adjusted and improved on the basis of the preliminary study. Factor loadings of all construct item were greater than 0.788, indicating that the scale had structural validity.

Constructs Item Measurement Sources
Business model innovation (BMI)

BMI1
The business model offers new combinations of products, services and information.
Zott et al. [49] BMI2 The business model, overall, offers high transaction efficiency. BMI3 The business model links participants to transactions in novel ways.

BMI4
The business model gives access to an unprecedented variety and number of participants and/or goods BMI5 Overall, the company's business model is novel.
Competitive strategy innovation (CSI)

CSI1
The company's strategy is different from others in the industry.

Markides [50] CSI2
The company pursued an unusual strategy. CSI3 The company's competitive strategy has huge potential value.

SF1
The enterprise can produce products with different raw materials.
Sanchez [28] SF2 The employees of the enterprise can be competent for various jobs.

SF3
The production equipment of the enterprise can carry out different operations.

SF4
The enterprise can produce products with different processes.

SF5
The production line of the enterprise can produce different types of products.

SF6
Enterprises can re allocate resources according to the needs of different products.

SF7
Enterprises are good at reconstructing the resource chain of products.

SF8
Enterprises can make corresponding changes to internal organizational processes. SF9 Enterprises can effectively create new resource combinations.

SF10
Enterprises are good at coordinating resources among various departments.

SF11
Enterprises have good internal operation coordination.

Constructs Item Measurement Sources
Sustainable development performance (SDP)

SDP1
Compared with the industry average, the growth rate of enterprise sales is fast.
Kostopoulos et al. [51] SDP2 Compared with the industry average, the growth rate of corporate profits is fast.

SDP3
Compared with the industry average, the growth rate of the market share of enterprises is fast.

SDP4
Compared with the industry average, the rate of return of enterprise investment grows fast.

SDP5
Compared with the industry average, enterprises have high return on assets.

SDP6
Compared with the industry average, enterprises have a high probability of success in developing new products and services.

SDP7
Compared with the industry average, new products and services are well received by the market.

SDP8
Compared with the industry average, the success rate of cooperation between enterprises and cluster members is high.

SDP9
Compared with the industry average, corporate profitability is high.

Correlation Analysis
Tables 4 and 5 show descriptive statistics of variables and the correlation coefficients between variables. The means for business model innovation and competitive strategy innovation were 3.836 and 3.25, respectively. This indicates that business model innova-tion and competitive strategy innovation are important for new ventures. The means of strategic flexibility was 4.058, respectively, showing that enterprises had a high degree of strategic flexibility. The results of correlation analysis show a strong correlation between business model innovation, competitive strategy innovation and sustainable development performance.

Model Estimation
To test all our hypotheses on the inverted-U relationship between business model innovation and sustainable development performance, as well as the moderating effects of competitive strategy innovation and strategic flexibility, we establish the following empirical model. SDP i = a 0 + a 1 *Year i + a 2 *Size i + a 3 *Type i + a 4 *Tech i + a 5 *Sale i + a 6 *SF i + a 7 *CSI i + a 8 *BMI i + a 9 *BMI 2 i + a 10 *BMI 3 i + a 11 * BMI i * CSI i + a 12 * BMI 2 i * CSI i + a 13 * BMI i * SF i + a 14 *BMI 2 i * SF i + u i Let i = 1 . . . N present new venture. BMI i and BMI 2 i are used to test the inverted-U relationship between business mode innovation and sustainable development performance. BMI 3 i is used to test the S−shaped relationship. BMI i * CSI i , BMI 2 i * CSI i , BMI i * SF i and BMI 2 i * SF i are interaction terms and express the moderating effects of competitive strategy innovation and strategic flexibility. The a 1 to a 12 are the parameters to be estimated. Additionally, u i is error term associated with observation i.

Results
We used the SPSS software to estimate this model. Table 6 presents the results of our regression by ordinary least square. The adjusted R-square of this model is reasonable, and the F-value is statistically significant. Variance inflation factor statistics of variables are less than 2.0, which means no significant multicollinearity among independent variables. We present the results of estimation hierarchically. We present results with control and independent variables in columns 1, then show the quadratic term and interaction terms in column 2, 3, 4, 5, 6 and 7. Hypothesis 1 predicted that an inverted-U relationship exists between business model innovation and sustainable development performance. According to the column 2 of Table  6, we found the evidence to support this hypothesis. The coefficient of BMI is positive and statistically significant (a 8 = 0.883, t = 8.717, p < 0.01), and the coefficient of BMI 2 is negative and statistically significant (a 9 = −0.112, t = −6.560, p < 0.01). When the level of business model innovation reaches the extreme, the level of sustainable development capability is highest. If the level of business model innovation is less than extreme, business model innovation positively affects sustainable development performance. If the business model innovation exceeds extreme, the effect of business model innovation on sustainable development performance begins to decline. However, the empirical results do not support S-shaped relationship because the coefficient of BMI 3 is not statistically significant (a 10 = −0.007, t = −1.479, p > 0.1) according to the column 3 of Table 6. Figure 2 shows the inverted-U relationship between business model innovation and sustainable development performance.
business model innovation exceeds extreme, the effect of business model innovation on sustainable development performance begins to decline. However, the empirical results do not support S-shaped relationship because the coefficient of BMI 3 is not statistically significant (a10 = −0.007, t =−1.479, p > 0.1) according to the column 3 of Table 6. Figure 2 shows the inverted-U relationship between business model innovation and sustainable development performance.  Table  6, we also found support for hypothesis because the coefficient of CSI (a7 = 0.460) is positive. The t−value of CSI coefficient is 10.518 and p < 0.01 mean that the coefficient of CSI is statistically significant at 0.01 levels.
Hypothesis 3 predicted that competitive strategy innovation positively moderates the inverted-U relationship between business model innovation and sustainable development performance. The empirical results of the column 5 of Table 6 demonstrate that the coefficient of the interaction term (BMI*CSI) is positive and statistically significant (a11 = 0.498, t = 3.264, p < 0.01), and the coefficient of the interaction term (BMI 2 *CSI) is negative and statistically significant (a12 = −0.106, t =−2.690, p < 0.01), supporting hypothesis 3. This result implies that competitive strategy innovation could moderate the inverted-U relationship between business model innovation and sustainable development performance. Figure 3 shows the moderating effect of competitive strategy innovation on the inverted-U relationship.  Table 6, we also found support for hypothesis because the coefficient of CSI (a 7 = 0.460) is positive. The t−value of CSI coefficient is 10.518 and p < 0.01 mean that the coefficient of CSI is statistically significant at 0.01 levels.
Hypothesis 3 predicted that competitive strategy innovation positively moderates the inverted-U relationship between business model innovation and sustainable development performance. The empirical results of the column 5 of Table 6 demonstrate that the coefficient of the interaction term (BMI*CSI) is positive and statistically significant (a 11 = 0.498, t = 3.264, p < 0.01), and the coefficient of the interaction term (BMI 2 *CSI) is negative and statistically significant (a 12 = −0.106, t = −2.690, p < 0.01), supporting hypothesis 3. This result implies that competitive strategy innovation could moderate the inverted-U relationship between business model innovation and sustainable development performance. Figure 3 shows the moderating effect of competitive strategy innovation on the inverted-U relationship. Hypothesis 4 posited that strategic flexibility positively influences sustainable development performance of new ventures. Our empirical results presented by column 1 of Table 6 proved hypothesis 4 because the coefficient of SF (a6 = 0.144) is positive. The t−value of coefficient is 2.890 and p < 0.01 mean that the coefficient is statistically significant at 0.01 level.
Hypothesis 5 predicted that strategic flexibility positively moderates the inverted-U relationship between business model innovation and sustainable development capability.  Table 6 proved hypothesis 4 because the coefficient of SF (a 6 = 0.144) is positive. The t−value of coefficient is 2.890 and p < 0.01 mean that the coefficient is statistically significant at 0.01 level.
Hypothesis 5 predicted that strategic flexibility positively moderates the inverted-U relationship between business model innovation and sustainable development capability. The empirical results of the column 7 of Table 6 demonstrate that the coefficient of the interaction term (BMI*SF) is positive and statistically significant (a 13 = 0.270, t = 2.229, p < 0.05), and the coefficient of the interaction term (BMI 2 *SF) is negative and statistically significant (a 14 = −0.112, t = −2.319, p < 0.05), supporting hypothesis 5. This result implies that strategic flexibility could moderate the inverted-U relationship between business model innovation and sustainable development capability. Figure 4 shows the moderating effect of strategic flexibility on the inverted-U relationship. Hypothesis 4 posited that strategic flexibility positively influences sustainable development performance of new ventures. Our empirical results presented by column 1 of Table 6 proved hypothesis 4 because the coefficient of SF (a6 = 0.144) is positive. The t−value of coefficient is 2.890 and p < 0.01 mean that the coefficient is statistically significant at 0.01 level.
Hypothesis 5 predicted that strategic flexibility positively moderates the inverted-U relationship between business model innovation and sustainable development capability. The empirical results of the column 7 of Table 6 demonstrate that the coefficient of the interaction term (BMI*SF) is positive and statistically significant (a13 = 0.270, t = 2.229, p < 0.05), and the coefficient of the interaction term (BMI 2 *SF) is negative and statistically significant (a1 4=−0.112, t =−2.319, p < 0.05), supporting hypothesis 5. This result implies that strategic flexibility could moderate the inverted-U relationship between business model innovation and sustainable development capability. Figure 4 shows the moderating effect of strategic flexibility on the inverted-U relationship.

Discussion
This study explored the inverted-U relationship between business model innovation and sustainable development performance of new ventures, as well as the moderating

Discussion
This study explored the inverted-U relationship between business model innovation and sustainable development performance of new ventures, as well as the moderating effects of competitive strategy innovation and strategic flexibility. We constructed a theoretical model and an empirical research model to investigate our research questions. Empirical research data were collected through 326 questionnaires to test our research hypotheses. Our research provides several theoretical contributions and implications for practice.

Theoretical Implications
This paper provides several important key findings and makes the following theoretical contributions to related literature. First, our research contributes to the literature on sustainable development performance of new ventures by combining business model innovation, competitive strategy innovation and strategic flexibility. Although extensive studies have investigated the isolated effects of business model [9] innovation, competitive strategy innovation [23] and strategic flexibility [29] on new ventures, scant research has combined those factors to explore their influences on the sustainable development capability of new ventures. The results of our research complement the previous literature on the sustainable development capability of new ventures.
Second, our research contributes to the literature on business model innovation by investigating an inverted-U relationship between business model innovation and sustainable development performance. Although extensive studies have explored the linear relationship between business model innovation and sustainable development capability [10,25], scant research has found the nonlinear relationship between them. Based on related literature, this paper builds a theoretical model to test the nonlinear relationship. Unlike prior literature [6,40] Third, our research extends related literature on competitive strategy innovation by incorporating the moderating effect of competitive strategy innovation on the inverted-U relationship between business mode innovation and sustainable development performance. Although previous studies have explored the role of competitive strategy innovation in enterprises [52], few have explored its moderating effect. The results of our research indicated that competitive strategy innovation positively moderates the inverted-U relationship between business model innovation and sustainable development performance. Unlike previous literature that researched the direct effects of competitive strategy innovation [23], our study focused on its moderating effect. Competitive strategy innovation is the expansion of innovative thinking at the strategic level. Competitive strategy innovation emphasizes the formulation of appropriate innovative competitive strategies to meet the market demand and adapt to developmental needs. Competitive strategy innovation enables new ventures to gain competitive advantages in the market. Hence, competitive strategy innovation can help new ventures overcome the constraints of existing market demands and product functions to obtain higher financial performance and competitive advantages, and then improve their sustainable development. High competitive strategy innovation enhances the positive effect of business model innovation and diminishes its negative effect on sustainable development performance. Therefore, the findings of this study complement previous studies on competitive strategy innovation and expand the application of competitive strategy innovation theory to the context of new ventures.
Fourth, our study enriches the research on strategic flexibility in the new venture context. Despite the prevalent research of strategic flexibility in the literature on new venture [28], scant research has investigated its moderating effect of strategic flexibility on the inverted-U relationship between business model innovation and sustainable development performance. Our study found that that strategic flexibility positively moderates the inverted-U relationship between business model innovation and sustainable development capability. Strategic flexibility depends on the use scope of existing resources, the cost of resource use conversion and the time required for resource use conversion. The higher the strategic flexibility of new ventures, the more extensive the use of resources and the lower the cost of use conversion and the faster the speed. Therefore, strategic flexibility could enhance the sustainable development of new ventures. High strategic flexibility strengthens the positive effect of business model innovation on sustainable development capability and weakens its negative effect on sustainable development performance. Conversely, low strategic flexibility diminishes the positive effect of business model innovation and enhances its negative effect on sustainable development performance. Hence, the result of our study contributes to the research on strategic flexibility.

Practical Implications
This research provides new insights into the management of new ventures as well as offering several practical strategies for leaders and practitioners. First, managers of new ventures should not only pay attention to the advantages of business model innovation, but also be aware of its risks. Our research pointed out that new ventures with low or high business model innovation have worse sustainable development performance than new ventures with appropriate business model innovation (An inverted-U relationship). Busi-ness model innovation can improve the value creation of new ventures, and competitive strategy innovation can help new ventures enhance their core competitiveness. However, excessive business model innovation may not be accepted by the market and stakeholders, improving related risks and reducing sustainable development performance. Any business model innovation must be tested by the market. Business model innovation of enterprises cannot be separated from the needs of the market and users. If business model innovation is not accepted by users and the market, it will eventually lead to failure. In addition, high business model innovation needs a lot of capital and resources, which leads to the fracture of enterprise capital chain and brings huge financial risks. Therefore, managers of small and medium-sized enterprises should adopt appropriate business models instead of pursuing innovation too much.
Second, managers of new ventures should pay attention to the direct effect and moderating effect of competitive strategy innovation. On the one hand, the innovation of competitive strategy can help new ventures establish competitive advantages and enhance their sustainable development performance. On the other hand, competitive strategy innovation positively moderates the inverted U-shaped relationship between business model innovation and sustainable development performance. Managers of enterprises can improve their competitive strategy innovation from three aspects; 1. enterprises should strive to reduce costs and commodity prices in order to maintain competitive advantage; 2. enterprises should provide innovative products and services to maintain customer loyalty; 3. enterprises should divide the market and customer groups more carefully, and then surpass the competitors in this range.
Third, new ventures should promote their strategic flexibility because it could positively moderate the inverted-U relationship between business model innovation and sustainable development performance. Strategic flexibility depends on the use scope of existing resources, the cost of resource use conversion and the time required for resource use conversion. The higher the strategic flexibility of new ventures, the more extensive the use of resources, the lower the cost of use conversion and the faster the speed. Therefore, strategic flexibility is very important for new ventures to improve their sustainable development performance of new venture. Enterprise managers can improve their own strategic flexibility from three aspects: 1. Enhance the strategic thinking ability of senior managers; 2. Enhance the response ability and execution ability of all employees to the enterprise strategy; 3. Improve the organizational learning ability of enterprises.

Limitations and Future Research
Although our research model uses the data from a survey to test our hypotheses, there remain some limitations. Firstly, the data in this paper are mainly from small and mediumsized enterprises in Guangdong Province of China, which may lead to regional sample bias. As Guangdong Province is the most developed region in China, this paper only uses the enterprises in this region as the research object, which may only reflect the phenomenon of the region, and then reduce the generality of our research results. Second, this paper mainly uses the research method of questionnaire survey, which may not accurately reflect the real situation of enterprises. Due to the subjectivity of the questionnaire survey, there may be personal subjective deviation in filling out the questionnaire, which leads to some deviation between the content of the questionnaire and the real situation of the enterprise. Third, the measurement of sustainable development capability in this paper mainly focuses on the financial and innovation indicators of enterprises, but ignores the environmental and social factors. Fourth, this paper uses only one period of research data, which cannot effectively explore the long-term effects of business model innovation and the changes of enterprises in different periods. Fifth, this study does not focus on specific types of enterprises and industries to provide specific business model innovation and sustainable development strategies for enterprise decision makers. Although this paper mainly analyzes various types of enterprises through questionnaire survey, this paper lacks the in-depth research on a specific type of enterprises. The practical implications of this survey based on multi types of enterprises may still be limited. This paper will make up for these deficiencies in future research. First, our research will collect data on small and medium-sized enterprises from different provinces in China, not just in one region. Second, we will try to use objective data to reflect the business model innovation, competitive strategy, strategic flexibility and sustainable development capability of enterprises. Third, this paper will combine financial, innovation, social and environmental factors to measure the sustainable development capability of enterprises. Fourth, our research will try to collect panel data including time series as the main research data. Fifth, in the foreign research, we will conduct in-depth analysis and exploration on the business model innovation and sustainable development strategy of several types of enterprises. Not only based on statistical data, our research will also provide more practical implications for specific types of enterprises by combining interviews and actual cases.

Conclusions
Although previous studies have pointed out that business model innovation positively affects the sustainable development performance of new ventures, little research has found the inverted-U relationship between them, as well as the moderating effects of competitive strategy innovation and strategy flexibility. To fill these research gaps, we developed an empirical model to test our research hypotheses. According to our findings, an inverted-U relationship exists between business model innovation and sustainable development performance such that new ventures with low or high business model innovation have worse sustainable development capability than new ventures with appropriate business model innovation. Moreover, we found that competitive strategy innovation and strategic flexibility enhances the inverted-U relationship between business model innovation and sustainable development performance. From a theoretical perspective, this paper establishes a research model to understand the sustainable development performance of new ventures and contributes significantly to the literature on business mode innovation, competitive strategy innovation, strategic flexibility and new ventures. From a practical perspective, this paper provides new insights into the management of new ventures and recommends several practical strategies for leaders and practitioners.