Received: 5 October 2019 Revised: 2 April 2020 Accepted: 24 May 2020 DOI: 10.1002/hpm.3012 R E S E A R CH A R T I C L E Endangering China's environmental health security goals through negative environmental investor behaviours Lulin Zhou1,2 | Maxwell O. Antwi1 | Henry A. Antwi2,3 | Ama Boafo-Arthur2,4 | Tehzeeb Mustafa2,3 1School of Management, Jiangsu University, Summary Zhenjiang, China 2Center for Health and Public Policy China sees the need to maximise its environmental health Research, Jiangsu University, Zhenjiang, China security as a major priority in its sustainable development 3Institute for Systems Engineering, Jiangsu agenda. This is at the heart of China's “ecological civilisation” University, Zhenjiang, China and “beautiful China” dream. One of the objectives of this 4School of Continuing and Distance dream is to sensitize investors to invest in health and envi- Education, University of Ghana, Accra, Ghana ronmental stocks to support environmental health goals. Correspondence However, both the Shanghai and the Shenzhen stock mar- Henry A. Antwi, School of Management, Jiangsu University, 301 Xuefu Road, kets continue to witness contemporaneous movement Zhenjiang, 212013, China. (herding behaviour) by investors from environmental stock to Email: asanteantwi2@yahoo.com perceived safer stocks and this is stifling the growth of the Funding information environmental health sector due to capital deprivation. Our Government of Jiangsu Province, Grant/ paper evaluates the significance and potential effect of this Award Number: 1102129C; Post-doctoral Foundation of China, Grant/Award Numbers: herding trend among environmental stocks using a collection 2018T60508, 2018M511705; National of sophisticated econometric models namely, the state-space Natural Science Foundation of China, Grant/ Award Numbers: 71904066, 71974079 model, enhanced state-space model, the cross-sectional SD (CSSD) and the cross-sectional absolute deviation (CSAD). The models are used to evaluate firm-level data collected from the 80 environmental stocks indexed by the KGRM MSCI China IMI Environment 10/40 Index. Three of the models confirm the presence of endemic negative (herding) investor behaviour among environmental stocks in China and this threatens the sustainability of environmental stock capi- tal to promote China's environmental health goals. We have proposed measures to ameliorate the risks posed by such negative contemporaneous investor behaviours. 1398 © 2020 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/hpm Int J Health Plann Mgmt. 2020;35:1398–1411. ZHOU ET AL. 1399 K E YWORD S environmental, health, herding behaviour, investor, stock market 1 | INTRODUCTION The effect of environmental degradation on human health and well-being has gained a self-perpetuating momentum across the globe since the early 1960s. Many countries have responded to the global call enacting various environ- mental health regulations, policies programs and thresholds.1 In most of these countries, both public and private organisations are required by domestic and international laws to design enduring sustainable mechanisms to mini- mize environmental health externalities associated with their operations.2 Since the United Nations Conference on Environment and Development (Rio de Janeiro Earth Summit, 1992), new frontiers in ecological health security have emerged beyond the previously known areas of environmental concern.3 Before this Earth Summit in 1992, environ- mental health security programs among countries focused mainly on natural and few built environmental factors that affect human health, for example, sanitation.4 Over time, and in response to the UN Decade of Education for Sus- tainable Development (2005-2014), a new sphere in environmental health security emerged to shift the paradigm to radically promote development that seeks to meet human development goals without compromising on the natural systems, resources and ecosystem upon which the global economy and society depends.4 Central to the new sphere in sustainable development is environmental health security. This interest is also due to the increase in the records of industry-induced health casualties over the world. The focus of new environmental concerns on environmentally responsible behaviours at all level of development keeps inspiring advanced research in pro-environment programs in China and many other emerging countries.5 China's ecological civilization program requires all manufacturing enterprises to adopt environmentally responsible manufacturing (ERM) practices to pre- vent, detect and respond to environmental-led calamities.6 China's industries are consciously but systematically readjusting their operational systems, skills, strategies, structures and shared values to positively alter the changing dynamics of the ecosystem and its resulting environmental health concerns.7 Most of the environmentally responsible business practices being pursued in China are economically driven system-wide and integrated strategies that seek to eliminate or reduce waste streams associated with supply chain, product and service design, manufacturing processes, product use and disposal of materials.8 Fundamental in this endeavour is the recognition that waste and pollution may have far-reaching environmental health security implica- tions. Despite the benefits of the previous generation of sustainable techniques that emerged in the early 1980s to support industries (just in time, total quality management, process reengineering, time-based competition, etc.), these alone have not been sufficient to safeguard concerns for the protection of the environment9 hence need for alterna- tive approaches. Further, as more and more industrial clusters emerge across China, another move to imbed sustain- able environmental health practices is driving collaborative networks so that group of firms can optimise environmentally responsible behaviours through shared resources. For example, Biotech, Medtech and Pharmaceuti- cal firms such as Jiangsu Hengrui Medicine, Fosun Pharmaceutical, Sinopharm Group, Harbin Pharmaceuticals, Guangzhou Pharmaceutical Holdings Limited in Jiangsu, Guangdong, Heilongjiang, Shanghai and Jiangxi Provinces have been successful in promoting greater environmental health security through self-regulating collaborative net- work of environmentally responsible policies, programs and standards.10 These industry-led initiatives have engen- dered more exceptional public support, renewed political commitment from top leaders and elicited massive government subsidies for these industries among others.10 Despite this seemingly successful effort in China's quest to secure its environmental health security goals, the strategies and policies are not without pitfalls. China believes that a flourishing environmentally stock market is essential to get the needed capital to consolidate environmental health goals.11 President's Xi's “ecological 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1400 ZHOU ET AL. civilisation” and “beautiful China” dream are founded on a strong public–private partnership through capitalisation of the environmental stock market. However, Ji and Zhang12 observed that the environmental stock market in China is not attractive to Chinese and foreign investors alike. In the last decade, the market has not been stable as investors move away in herds to perceived safer stocks intermittently in response to both internal and external shocks. For example, high environ- mental tariff, tight ecological inspections, closed-down of non-compliant producers have affected investor confi- dence in the sector. Further, the regulations for new energy vehicles announced by the government in September 207 helped the dominance and surge in the stock price of BYD (Chinese electronic car manufacturer).12 Yet this sudden decision failed to give non-Chinese makers enough time to prepare, such as building new plants and designing new models, effectively ensuring fines or forcing them to buy high-priced credits from Chinese manufacturers once the regula- tions go into effect.12 When the stock market growth is created by such an artificial process as in the case of BYD, external and institutional investors become apprehensive as they do not know the next move of the state, which can potentially affect the profitability of their investments in the environmental stock market.13 The logical thing is for the investors to flee in herds (en-mass) to safer investments making the sector vulnerable to investor herding behaviour.14 A recent study by KraneShares (a company that sponsors an exchange-traded fund attached to the China environmental health theme) reported on the challenges of the environmental stock market due to frequent environmental stock market fluctuations (returns and prices). Similarly, Broadstock & Cheng15 also noted that over 50% of ecological stocks in China are overweighted and vulnerable to investor shifts when policies become less favourable. This tendency has the potential to increase market uncertainty and further compound the rate of mass and unexpected herding of investors from the environmental health market in China. This pattern is suspected to be responsible for the nearly 6.4% decline in the KraneShares MSCI China Environment Index from June 2018 to April 2019. Moreover, as the rate of economic growth begins to slow down in China, environmental investors are more con- cerned with the need to preserve their capital and have begun deserting long-term investment strategies in the envi- ronmental stock market. They are instead opting for more stable and short-term markets such as the healthcare industry.16 China's culture is highly collectivist as such investors tend to influence many others when they decide to shun a particular market. If this happens in the environmental stock market, the capital needed to stimulate environ- mental health security goals will reduce.17 Several studies have already been conducted regarding herding behaviour in other stock markets in many countries including China, but not much has been done in the case of the environ- mental stock market in China and its repercussions on environmental health security. These studies have also dif- fered in the methodologies used as well as the outcomes they identified. For example, Christie and Huang17; Chang et al18 and Demirer and Kutan19 studied herding behaviour based on rational asset pricing conducted on securities in the United States, Europe and China, respectively. These studies observed that herding behaviour contributes significantly to the return on securities during market recessions. Demirer et al20 also analysed the existence of investor herding behaviour among 60 highly capitalised stocks based on a cross-sectional SD model. The study did not find herding behaviour among investors during period of economic stress. A similar study was conducted in the crude oil and heating oil capital markets by Uchida and Nakaga.21 The authors used a local-stochastic volatility (LSV) model known as the cross-sectional variability of factor sensitivities to analyse data on daily returns of the stock market. Chen et al14 developed it for the Japanese securities market and their results confirmed that investor do herd on the stock market. In the healthcare sector, Lulin et al22 explored the effect of investor herding behaviour on the Chinese stock markets, whereas Tripathi et al23 used herding techniques to study quarantine behaviour during the epidemic to support control. Similar industry-level studies by (Hwang and Salmon,24 Chang,25 and Flammer26) are documented in the existing literature with conflicting outcomes based on the differences in the analytical procedure used. This study is seeking to find out whether the environmental stock market in China also experiences investor's herding behaviour. This is done by assembling a collection of four sophisticated econometric models, namely the 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License ZHOU ET AL. 1401 state-space model, enhanced state-space model, the cross-sectional SD (CSSD) and the cross-sectional absolute deviation (CSAD). We then compare the results of the four methods to determine whether they prove that indeed, there is investor's herding behaviour in the environmental stock market in China. If this is the case, we can then argue that environmental health security in China is endangered by harmful investor behaviour on the stock market. To the best of our knowledge, this study is the first to apply the econometric model to determine investor's herding behaviour in the environmental stock market. Moreover, this study is innovative because we apply the models to firm-level data instead of industry-level data, which have predominantly been employed in the earlier studies. We also use the daily equally weighted index returns data from the selected environmental stocks on the Shenzhen, and Shanghai stock markets. The Hong Kong stock market is included for standardisation purposes. The three stock markets are essential for this study because they have a high presence of both domestic and foreign investors. Previous researchers have posited that foreign investors with higher information asymmetry tend to herd more than local investors. We briefly explain our methodology, the source of data and analytical procedure and pre- sent the empirical. We conclude the study by explaining the environmental health policy implications and future research direction. 2 | MATERIALS AND METHODS 2.1 | Data selection We collected the data on the 80 environmental stocks indexed on the MSCI China IMI Environment 10/40 from two main sources. Firstly, performance data were collected from May 2015 to August 2017 from the Shenzhen and Shanghai stock exchanges since the KGRM MSCI China IMI Environment 10/40 Index was not established within the period. Data from September 2017 to April 2019 were, however, collected from the KGRM MSCI China IMI Environment 10/40 Index. Since its launch, the KGRM MSCI China IMI Environment 10/40 Index has become a benchmark for investors that identify with China's sustainability vision and wants to encourage environmentally responsible business practices.27 We applied a strict data inclusion and exclusion criteria to eliminate outliers, clerical errors, empty and partially recorded information as well as other glaring mistakes in the data. The final results yielded a total of 116 800 aver- age daily returns of 80 environmental stocks for the period under consideration. The 80 stocks were further grouped into the four sectors, namely power generation, materials, automobile and environmental solution per MSCI classifi- cations. We studied the stocks in groups in order to quickly identify herding syndromes in a homogeneous trade where the members face the same decision problem. The daily return of the securities was computed based on the equally weighted portfolio for the 80 stocks, and the summary statistics is presented in Table 1. Table 1 also shows the proportion of both domestic and foreign investors in the four sectors. This helps to verify the claim that investor groups (where trade is sufficiently homogeneous) are more susceptible to herd than individual investors. Generally, Table 1 shows persistent growth in the number of foreign investors in the four sectors from 2015 to 2019. Table 2 shows the summary statistics for the log of the average daily return, the average number of companies and return dispersion used in computing the individual statistics for the sectors. Panel A shows that the average daily returns are positive for the four sectors. Panel B, on the other hand, shows the summary statistics for daily cross- sectional SDs within each sector. Both Panel A and Panel B show that the volatility cross-section in the automobiles sector is relatively high. 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1402 ZHOU ET AL. TABLE 1 Percentage of share holders in the market by sector (%) Power generation (%) Materials (%) Automobile (%) Environmental solution (%) Domestic Domestic Foreign Domestic Domestic Foreign Domestic Domestic Foreign Domestic Domestic Foreign Year individual institution investor individual institution investor individual institution investor individual institution investor 2015 92.8452 3.1066 3.0482 93.7272 1.7056 4.1872 92.4242 0.392 6.9638 91.4242 0.392 7.2638 2016 92.7472 0.784 6.3986 90.7676 1.539 6.7232 83.1522 0.5096 14.308 80.2522 0.5096 18.308 2017 88.6312 0.8526 9.5162 88.3372 1.6272 9.9572 80.9484 0.4606 18.231 79.9484 0.4606 18.631 2018 87.4552 0.8918 10.653 89.0134 1.3234 9.2232 85.9366 0.735 12.3284 84.9366 0.735 13.3284 2019 83.7116 0.8918 14.3966 73.6902 1.882 24.4278 81.8892 0.5292 16.5914 80.8892 0.5292 17.5914 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License ZHOU ET AL. 1403 TABLE 2 Summary of the statistics Sector # Firms # Obs. Mean SD for the average daily returns and the cross-sectional SDs Panel A: Average daily return Power generation 16 23 360 0.02% 2.41% Materials 32 46 720 0.02548 2.3559 Automobiles 17 24 820 0.02744 2.7901 Environmental solutions 15 21 900 0.01372 2.6185 Panel B: Cross-sectional standard deviation Power generation 1.53% 0.89% Materials 1.94922 0.6909 Automobiles 1.957 0.7105 Environmental solutions 2.07662 0.5968 2.2 | Analytical procedure Four different but related econometric models were employed to test the presence of investor's herding behaviour among the 80 environmental stocks on the Shenzhen, Shanghai and the Hong Kong Stock Exchanges. These were two return dispersion models (CSSD and CSAD) and two state spaced models. The first return dispersion models namely cross-sectional SD (CSSD) measures the presence of herding behaviour as follows: uvuffiPffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiu Nt ðr −r Þ2i,t p,t CSSDt= i=1 ð1Þ N−1 where n denotes the number of companies in the aggregate market portfolio, whereas ri,t denotes the stock return observed on the company i for day t and rp,t is the cross-sectional average of the n returns in the market portfolio for day t. This measure also denotes the individual security returns dispersion close to the market average. The key idea in this model is that herd behaviour prevents the return of securities from deviating away from the overall market return since it is assumed that individuals invest largely based on the collective actions in the market. Another advan- tage of this approach is that it assumes that herding behaviour may largely occur during extreme market movements as investors will usually opt for market consensus during such period. The return dispersion measure in Equation (1) during market stress is estimated using a regression equation CSSDt = α+ βDD L t + β D U U t + εt ð2Þ where DLt = 1, if the aggregate market portfolio return on day t lies in the lower tail of the return distribution; 0 other- wise, and DUt = 1, if the aggregate market portfolio return on day t lies in the upper tail of the return distribution; 0 otherwise. Since the formation of herd behaviour means imitating the market consensus, obtaining negative and statistically significant βD (for down markets) and βU (for up markets) coefficients implies the presence of herding behaviour among the market participants. This method has been used successfully in earlier studies by Huang, HuiYing et al,28 Ji and Zhang14 and returned good results. The second return dispersion model used for this study is proposed by Chang et al.24 This model uses the cross-sectional absolute deviation of returns (CSAD) as a proxy to measure return dispersion (CSAD). This idea is expressed mathematically as 1XN CSADt = j rN i,t−rm,t j ð3Þ i=1 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1404 ZHOU ET AL. This model disagrees with the assumption of the capital asset pricing model (CAPM). Instead, it believes that return dispersion and market returns have a linear relationship and that is expressed mathe- matically as CSADt = α+ γ1jrm:tj+ εt ð4Þ The argument of Chang et al24 who is the originator of this model is that market recession leads to the formation of a non-linear relationship between market return and return dispersion instead of the linearity assumption pro- posed in the CAPM. To date, this model has been applied to different studies with a robust outcome. For example, Akerlof and Shiller29 successfully applied this model to detect herding behaviour robustness of reference in different industries and markets. This study adopts but modifies the quadratic form of Chang et al' s26 general quadratic rela- tionship between CSADt and rm,t as follows: CSADt = α+ γ1jrm:tj+ γ2r2m:t + εt ð5Þ This model measures herd behaviour by looking at the proportional increases in the cross-sectional absolute deviation (CSAD) during extreme market movements. Herd formation will show in this case with a negative and sta- tistically significant non-linear coefficient γ2 and vice versa. The second model used to measure herding behaviour among environmental stocks on the Chinese stock mar- kets are the state-space models. Consistent with earlier works of Hwang and Salmon,22 the measurement of herd behaviour in state-space models has based on cross-sectional variability of factor sensitivities instead of returns. In the first case as proposed by Hwang and Salmon 2004, the relative dispersion of the betas of the securities in the market is estimated as follows ErðritÞ= βimtEtðrmtÞ ð6Þ where rit and rmt are the excess returns on asset i and the market at the time t, respectively, βimt is the systematic risk measure, and Et() is the conditional expectation at the time t. In equilibrium, only β is needed to price an asset i. The fundamental idea in this third model is that investors do not seek equilibrium relationship of Equation (5) in a herd behaviour condition but match their assets with the market return and this gives a bias β term and a commensurable expected rate of return. This is measured as follows Ebt ðritÞ b ð Þ = βimt = βimt−hmtðβE imt−1Þ ð7Þt rmt where Ebt ðritÞ and βbimt are the market's biased short-run conditional expectation on the excess returns of asset i and its beta at the time t, and hmt is a latent herding parameter that changes over time, hmt≤1, and conditional on market fundamentals. As noted by Hou & Li,30 herding behaviour is present when (0 < hmt<1) then some degree of herding exist on the market, but the hmt defines its intensity. For the total asset, a measure of herding behaviour is estimating using the SD of βbimt which is formulated as follows   rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Std bc βimt = Ec ðβimt−h 2mtðβimt−1Þ−1Þ = Ec ðβimt−1Þ2 ð1−hmtÞ= StdcðβimtÞð1−hmtÞ ð8Þ   where EC( ) represents the cross-sectional expectation, Std βbc imt is the time-varying interval in response to herding behaviour in the market. In its log form the equation is expressed as follows 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License ZHOU ET AL. 1405    log Std βbc imt = μm + υmt ð9Þ   where μm = E[log[Stdc(βimt)]] and υ ii~mt d 0,σ2mυ the first state-space model is expressed mathematically as    log Std βbc imt = μm +Hmt + υmt, ð10Þ   Hmt =ϕmHmt−1 + ηmt, where Hmt = logð1−hmtÞ and ηmt  iid 0,σ2mη ð11Þ Regarding the third model, the focus is basically on the dynamism in the movement patterns in the latent state variable, Hmt, the state-space model equation. Herding behaviour is deemed to exist in the market when σ2mη =0 and significant, which implies that Hmt = 0 for all t. A unique aspect of this model for measuring herding behaviour is that herding behaviour Hmt is viewed as a dynamic process that evolves. When the ϕ is also significant, it means the structure of herding behaviour is autoregressive. The fourth model to estimate the presence of herding behaviour in the environmental stock market in China and which is an enhanced or augmented state-space model seeks to increase the first state-space model to ensure the robustness of inference. This is done by simply adding market volatilitylogσmt to Equation (8) and return, rmt, as an independent variable to create an augmented state-space model expressed mathematically as;    log Std bc βimt = μm +Hmt + cm1logσmt + cm2rmt + υmt: ð12Þ The interpretation of this model follows consistently with the interpretation of the first state model. 3 | RESULTS In Equation (2), the Newey-West heteroskedasticity and autocorrelation consistent standard errors were used to estimate the CSSD (herding behaviour) among environmental stocks in China due to the significant variation in dis- persion and strong correlation. The MSCI China Environment Index represents the market while the lower and upper one and five percentile of the market returns represents market stress. The results of Equation (2) presented in Table 3 show that the (βD) values are positive and statistically significant and this validates the capital asset pricing model that equity return dispersion is high when prices are rising. TABLE 3 Coefficient of regression for CSSD = α+ β DL Ut D t + βUDt + εt Market return in the extreme upper/ Market return in the extreme upper/lower Return Dispersions lower 1% of the return distribution 5% of the return distribution Sectors α βD βU α βD βU Power generation 1.45% 0.14% 0.194%** 1.33% 0.454%*** 0.169%*** R2 (0.442) (0.405) (0.357) (0.456) Materials 1.819 0.699*** 0.442*** 1.6895 0.541*** 0.451*** R2 (0.471) (0.490) (0.577) (0.327) Automobile 1.758 0.167 0.026 1.7218 0.497*** 0.160*** R2 (0.519) (0.514) (0.457) (0.404) Environmental Solutions 2.073 0.146 0.149* 2.048 0.449*** 0.142*** R2 (0.493) (0.414) (0.457) (0.470) 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1406 ZHOU ET AL. Table 4 presents the estimate of herding behaviour based on the alternative CSAD non-linear Equation (4). Con- sistent with the earlier suggestions by Chang et al (2000), three different regression models were run for each sector. The first regression model used the entire sample, whereas the remaining two regressions were applied only to the restricted data on the fluctuations in the market index (up and down markets streams). Using different models help to detect an asymmetric effect in investor's herding behaviour. The higher R2 values of the non-linear CSAD model show that it fits better than the CSSD model; hence, its estimates are more credible. Thus, the outcome in Table 4 is more reasonable than those in Table 3 since the proportion of variation in the herding attributed to the independent variables is higher. Since the first non-linear term (γ2) in the CSAD model is statistically significant, that estimate is used to infer herding behaviour, and it prevails in the four sectors analysed. The γ2 in Table 4 is negative and statistically significant, and that suggests a non-linear and declining relationship between market return and equity return dispersion. The regression model applied to the restricted data (up and down markets streams) shows that investors herd during market losses for all the sectors. Table 5, on the other hand, presents the result of herding behaviour using the first state-space model. Similar to the CSAD, the first state-space model shows a high persistent, Hmt which is strong and statistically significant, and that confirms the presence of investor herding behaviour. The ϕ̂m estimates are highly persistent improve, and the σmη values are large and statisti- cally significant. This further confirms the presence of herding behaviour among environmental stocks across the sectors. The results from the second state-space model in Table 6 also affirm the robustness of inference of herd behaviour noted among the environmental stocks using the CSAD and the first state-space model. In the second model, two additional market variables (market return and market volatility) are added to better estimate the degree of herding, given the state of the market. The results show that the inclusion of market returns and market volatility variables does not affect the statistical significance of Hmt. Secondly, changes in the volatility of factor sensitivities or dispersion in the betas for the 80 environmental stocks denoted by Std βbc imt could be attributed to investors' herding behaviour, and not just changes in market fundamentals. Table 6, on another hand, shows that the coefficients for the market vo latility term (logσmt) are positive and sta- tistically significant. This means that the volatility of factor sensitivitiesStd βbc imt , in all the four sectors, grows in the same direction with market volatility. That observation affirms previous studies such as References 9,12,31,33 and 34 that investors tend to herd during highly volatile market conditions. This notwithstanding, the results in Table 6 show that the dispersion of the betas Stdc β b imt , for all stocks in the materials and environmental solution sectors, is significantly higher than in the other sectors. This is not surprising because in Table 1, the materials and environmen- tal solutions sectors have the highest numbers of foreign investors and this may support previous findings34,35 that foreign investors tend to herd more than domestic investors. Another observation is the relatively high value for ϕ̂m the materials and environmental solutions sectors. Besides, having more foreign investors than the others, the com- bined percentage of stocks within these sectors is approximately 59%. This high volume and value of trade make the two sectors highly susceptible to investor's pro-cyclical behaviour. 4 | DISCUSSION OF FINDINGS The objective of this research is to examine whether the environmental stock market investors in China exhibit this kind of behaviour and to what extent. We are inspired by the view that the stability of the environmental stock mar- ket in China is critical to the attainment of the overall sustainability objectives of the world's largest producer of car- bon emissions and for that matter its environmental health security. The behaviour of investors in the environmental stock market can potentially affect China's environmental health security goals. Herding behaviour, which is a con- temporaneous loss of investor confidence and movement from environmental stocks to perceived safer stocks by investors, is a major challenge in the realisation of China's environmental health goals. This study applied an 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License ZHOU ET AL. 1407 TABLE 4 Coefficient of regression for CSADt = α+ γ1jr 2m:tj+ γ2rm:t + εt Absolute deviation Whole sample Down market (Rm < 0) Up market (Rm > 0) Sector α γ1 γ2 α γ1 γ2 α γ1 γ2 Power generation 1.016 0.162*** −0.017*** 0.981 0.117*** −0.029*** 1.02508 0.095** −0.003 R2 (0.593) (0.732) (0.605) (0.467) (0.673) (0.645) Materials 1.196 0.193*** −0.013** 1.150 0.165*** −0.024*** 1.09858 0.117*** 0.0004 R2 (0.791) (0.582) (0.701) (0.504) (0.714) (0.544) Automobile 1.111 0.404*** −0.044*** 1.153 0.371*** −0.056*** 1.12308 0.121*** −0.029*** R2 (0.671) (0.638) (0.604) (0.613) (0.573) (0.727) Environmental Solutions 1.214 0.129*** −0.040*** 1.327 0.171*** −0.049*** 1.39258 0.169*** −0.017*** R2 (0562) (0.561) (0.619) (0.654) (0.589) (0.789) 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1408 ZHOU ET AL. TABLE5 State space model 1 forIndustry μ ϕm σmυ σmη log Stdc β b imt = μm +Hmt + υmt and Power −0.675*** 0.940*** 0.075*** 0.099*** Hmt = ϕmHmt−1 + ηmt generation (0.667) (0.620) (0.657) (0.654) Materials −0.645*** 0.940*** 0.019*** 0.091*** (0.675) (0.604) (0.574) (0.552) Automobile −0.570*** 0.945*** 0.047*** 0.091*** (0.496) 90.561) (0.752) (0.520) Environmental −0.647*** 0.957*** 0.040*** 0.067*** Solutions (0.496) (0.561) (0.752) (0.520)    TABLE 6 State-space model 2 log Std βbc imt = μm +Hmt + cm1logσmt + cm2rmt + υmt and Hmt = ϕmHmt−1 + ηmt Industry μ ϕm σmυ σmη logσm rm Power generation 0.451*** 0.941*** 0.075*** 0.097*** 0.659*** −0.005 R2 (0.704) (0.070) (0.904) (0.727) (0.754) (0.640) Materials 0.879*** 0.971*** 0.019*** 0.091*** 0.672*** 0.005 R2 (0.607) (0.575) (0.676) (0.775) (0.560) (0.706) Automobile −0.747*** 0.944*** 0.047*** 0.091*** −0.151*** 0.046 R2 (0.572) (0.741) (0.891) (0.795) (0.667) (0.510) Environmental Solutions 0.897*** 0.977*** 0.040*** 0.067*** 0.776*** 0.027 R2 (0.665) (0.721) (0.584) (0.650) (0.614) (0.704) ensemble of more sophisticated econometric models to firm-level data of 80 environmental stocks classified into four main sectors by the KGRM MSCI China IMI Environment 10/40 Index. Apart from the cross-sectional SD model, the remaining three robust models namely the cross-section absolute deviation, state-space model and augmented state-space model yield evidence of endemic herding tendencies among the environmental stocks on the Chinese stock market. The literature presented earlier shows an enormous amount of studies that warn of the dire consequence of persistence herding behaviour on any stock market. For example, the destabilising effect of investor herding behaviour on stock price synchronicity as validated in Reference 18 and that potentially stimulate sharp fluctuation in environmental stock prices en masse. The impact of such abrupt changes is loss of investor confidence, disinterest and diversion of capital to safer securities.29 The resulting investor disinterest deprives the sector of the needed capital and this can stagnate the sector and that may result in substantial negative ramification for other “sustainability dependent” sectors, including food security and public health safety. While China has achieved high economic growth in the last two decades, and has successfully lifted many of its citizens out of poverty, a quarter of its population has access to substandard tap water, 122 million Chi- nese still lives below the international poverty line and over 100 million have low-level social security and this can be compounded by weak environmental market. A decade ago, Akerlof and Shiller29 warned about ramifying effect of this impending danger as a result of economic behaviour of human beings similar to animalistic instincts. Secondly, a weak private sector support for China's ecological civilization and environmental health goals due to investor disin- terest may force China to divert resources intended for other critical social sectors to meet the sustainability objec- tives in response to excessive global pressure on China. There is also the danger of developing an environmentally responsible society that is overly controlled by the state as it may result in higher environmental taxes and charges with paradoxical consequences.30 In the BYD case recounted in earlier sections of the paper, government must 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License ZHOU ET AL. 1409 desist from sudden and seemingly bais announcement of strict regulations that tends to create doubt in the minds of foreign investors. The state must find alternative ways to provide support for local industries to compete at par with international ones instead of creating artificial conditions for them to excel. This may avert a potential and an unprecedented crash in the environmental stock market if herding behaviour persists among investors. Moreover, China's 13th 5-year Plan lacks precision on public–private consensus building and investor sensitisation to avert any panic response to changes in market conditions.20 As domestic investors are less likely to herd, equipping them to reduce better exposure to fluctuations is needed to support the sustainable goals. Further, China must use its experi- ence and leadership in sustainable development policies to highlight its readiness to engage the global investor com- munity and reduce the unintended opaqueness and uncertainty that usually hover around media portrayals of China's investment terrain.31 This may help foreign investors to confidently explore all the available opportunities the environmental stock market offers them to the hilt. 5 | CONCLUSIONS The destructive health effect of global warming and other environmental damages is well documented at the beginning of this paper. For example, drywalls that are cheaply produced in China have the potential to emit high levels of sulphur gas that corrodes electrical wiring and also causes breathing problems, bloody noses and headaches for building occu- pants. A recent study conducted by Scientific American found out that household contaminants such as phthalates which is a hazardous chemical emitted by vinyl floors, cause autism in kids. Similarly, women exposed to high levels of polybrominated diphenyl ether (PBDE) flame retardants common in cushions, carpet padding and mattresses have a 97% chance of acquiring poisonous chemicals in their bloodstreams and can avert or abort the pregnancy or suffer from other fertility issues, as a result. These health impacts of poor environmental control cannot be disregarded. Significantly, China's effort at meeting its environmental health goals through sustainable development occupied several pages of the inaugural address of President Xi Jinping at the 18th National Congress of the Communist Party of China, July 2018. This “beautiful China” dream that outlines China's ecological civilisation has become a global blueprint document not only for China but also its nearest neighbours and friends. However, the availability of capi- tal and the confidence of investors are critical to the attainment of this objective. The extent to which herding or procyclical behaviour exists on the Chinese environmental stock market was examined in this paper. The results con- firm the presence of endemic herding behaviour on the environmental stock market, and this can threaten the stabil- ity of the environmental health security once it depends on funds from environmental stock investments. We note that investors mostly herd during a period of market stress, and this is more prevalent among foreign and group of investors. We have proposed measures to improve the risk posed by such behaviours. Further research is needed in other countries, especially among the BRICS using the same models to validate the generalizability of this observed herding behaviour among environmental stock investors. ACKNOWLEDGEMENTS The authors are indebted to the National Natural Science Foundation of China (Grants nos. 71974079, 71904066) for supporting this project. The Post-doctoral Foundation of China (2018T60508, 2018M511705 and 2018T60508) and the Post-doctoral Foundation of Government of Jiangsu Province number 1102129C also supported this project. CONFLICT OF INTEREST The authors declare no potential conflict of interest. ETHICS STATEMENT This article does not require any human/animal subjects to acquire such approval. 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License 1410 ZHOU ET AL. ORCID Henry A. Antwi https://orcid.org/0000-0002-6595-2964 REFERENCES 1. Shen K, Li L, Liu J, Chen C, Liu J. Stocks, flows and emissions of DBDPE in China and its international distribution through products and waste. Environ Pollut. 2019;250(3):79-86. 2. 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Accounting. 2019;5(2):81-90. How to cite this article: Zhou L, Antwi MO, Antwi HA, Boafo-Arthur A, Mustafa T. Endangering China's environmental health security goals through negative environmental investor behaviours. Int J Health Plann Mgmt. 2020;35:1398–1411. https://doi.org/10.1002/hpm.3012 10991751, 2020, 6, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hpm.3012 by University of Ghana - Accra, Wiley Online Library on [06/11/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License