Abstract
This article examines the role of pension fund investments in shaping volatility dynamics in South African stock markets from 2010Q1 to 2022Q4. The article measures exchange rate volatility using the family of autoregressive conditional heteroskedasticity and Markov-switching dynamic regression. Results indicate that increased contributions by both individuals and employers are positively associated with higher stock market returns, suggesting a potential contribution to improved market performance. In addition, there are two distinct regimes when analyzing the impact of pension fund withdrawals on stock market volatility. In regime 1, pension fund withdrawals contribute to a decrease in stock market volatility, indicating a potential stabilizing effect on the market. However, in regime 2, higher withdrawals are associated with increased volatility, possibly reflecting market uncertainties and selling pressures. Given these, pension fund participants and investors should carefully consider the timing and amount of their withdrawals, taking into account the potential impact on stock market returns. Encouraging higher pension fund contributions by individuals and employers can play a crucial role in enhancing stock market performance and stability. Policymakers should closely monitor the impact of pension fund dynamics on market dynamics and ensure the integrity and stability of the stock market.
Keywords
Introduction
Stock market volatility has long been a subject of interest for researchers and policymakers alike. Understanding the factors contributing to volatility is crucial for investors, pension fund participants, and regulators seeking to maintain market stability and enhance financial performance. Among these factors, the role of pension fund investments in shaping stock market dynamics has received increasing attention in recent years. The South African stock market, as one of the largest and most influential in Africa, has witnessed significant growth and development over the past decade. With the increasing participation of pension funds in the market, it is imperative to examine the impact of their investments on stock market volatility in South Africa. Several studies have investigated the impact of pension fund investments on stock market development. Bayar et al. (2022) found that stock market development significantly affects the pension funds and insurance sectors in the short-term and that pension funds positively influence stock market development in Brazil, Chile, Hungary, Mexico, Peru, and South Africa. Similarly, Morina and Grima (2022) reported a positive link between pension fund investments and economic growth in non-OECD countries. Studies on pension funds and stock market volatility show mixed results: Fernandez (2014) found a mild effect of pension fund holdings on Chilean stock volatility; Thomas et al. (2014) observed a negative relationship in 34 OECD countries; Sanusi and Kapingura (2021) reported negligible effects on investment and growth in South Africa; and Xue et al. (2021) noted that while mutual funds reduced idiosyncratic volatility in developed markets, the effect was insignificant in emerging markets.
Despite the growing role of pension funds in South Africa, their impact on stock market volatility across different regimes remains unclear (Bayar et al., 2022; Sanusi & Eita, 2022; Sanusi & Kapingura, 2021). This gap constrains effective policy formulation and risk management. This article investigates the impact of expenditure (benefits paid and withdrawals) and income (member and employer contributions) of private pension and provident fund components on stock market volatility. Findings provide policymakers with insights to enhance market stability, protect investors, and ensure pension fund sustainability. Understanding these effects also helps investors make informed decisions and navigate market fluctuations confidently.
This article examines the impact of pension fund withdrawals, member contributions, and employer contributions on stock market performance and volatility across different regimes in South Africa. Using quarterly data from 2010Q1 to 2022Q4, the study employs autoregressive conditional heteroskedasticity (ARCH)-based volatility measures and a Markov-switching dynamic regression (MSDR) framework to capture regime-dependent dynamics and transition probabilities in both stock market returns and volatility. The results indicate that pension fund contributions from both members and employers are positively associated with stock market returns, underscoring their role in supporting market performance. In contrast, the effects of pension fund withdrawals on stock market volatility are regime-specific. In the first regime, withdrawals reduce volatility, suggesting a stabilizing effect, while in the second regime, higher withdrawals increase volatility, reflecting heightened market uncertainty and potential selling pressures. These findings highlight the importance of the timing and scale of pension withdrawals in shaping market outcomes.
The article is organized as follows: the following section presents the literature review, followed by the methodology and results of the study, and lastly the conclusion.
Literature Review
Various theories examine private pension funds, their strategies, and market impacts. Portfolio theory recommends diversifying across asset classes to balance risk and return and manage stock market volatility (Mittal et al., 2022). Lifecycle investing tailors asset allocation to age, reducing exposure to high-risk assets over time, potentially mitigating market volatility (Bodie, 2015). Behavioral finance highlights how psychological biases and herd behavior can amplify volatility, particularly during market stress (Fakhry, 2016).
Fernandez (2014) examined 42 Chilean firms from 2002 to 2008 using Arellano–Bond regressions, finding that pension fund holdings have a mild effect on stock return volatility, and higher volatility reduces pension fund holdings, suggesting a preference for safer stocks. Thomas et al. (2014) analyzed 34 OECD countries from 2000 to 2010 with panel dynamic regressions and reported a negative relationship between pension fund equity shares and market volatility. Gökçen and Yalçın (2015) applied factor models in Turkey from 2004 to 2011 to explain 76%–95% of fund returns variations. Bayar (2016) found that private pension funds positively influence the long-term growth of Turkey’s debt and stock markets and exhibit causal links among these markets. Alda García and Marco Sanjuán (2017) observed that domestic equity pension funds in eight European countries from 1995 to 2014 positively affect market size, returns, and stability, especially in the short-term. Staveley-O’Carroll and Staveley-O’Carroll (2017) showed that government-managed pensions in the USA and China influence private savings, capital allocation, and portfolio risk. Alda (2017) found that pension funds have become dominant in 13 European stock markets from 1999 to 2014, with effects varying over time due to adaptive managerial strategies. Coşkun et al. (2017) demonstrated in Turkey (2006–2016) that capital market development has a long-run cointegrating relationship with economic growth, with causality running from markets to growth.
De la Torre-Torres et al. (2018) examined Mexican public pension funds from 2005 to 2018 using a Markov-Switching model, which demonstrated that short-term underperformance in socially responsible equities does not persist long-term, with two regimes showing better outcomes during distress periods. Chovancova et al. (2019) analyzed pension fund portfolios from 2005 to 2015 and reported that bonds have a stronger impact on performance than stocks. Brzeszczyński et al. (2019) studied large capital inflows in a thin market from 2000 to 2018 and found that pension fund flows have negligible long-term effects on stock prices, questioning the hypothesis of information-based trades. Babalos and Stavroyiannis (2020) used panel vector autoregression (VAR) across 29 countries, showing that pension fund equity investments enhance stock market development, with significant bidirectional Granger causality between market development and pension fund investments.
Shen et al. (2020) examined Chinese pension funds (2007–2016) using a four-factor model and found that only 5 of the 16 entrusted funds generated positive risk-adjusted returns, suggesting a principal–agent problem. Daradkah and Al-Hamdoun (2021) used autoregressive distributed lag (ARDL) co-integration in Jordan from 1980 to 2017 and found a significant short-run relationship between pension funds and capital market development. Sanusi and Kapingura (2021) applied Bayesian linear regression in South Africa from 1990 to 2019 and reported negligible effects of pension funds on investment and growth. Holzner et al. (2022) demonstrated that public pension expenditures and fund assets reduce per capita consumption and macroeconomic volatility across 35 OECD countries from 1980 to 2018. Xue et al. (2021) showed that pension funds strongly stabilized country-specific market risk in 47 global markets, outperforming mutual funds, particularly in emerging markets. Babalos et al. (2021) analyzed US equity fund flows from 2000 to 2015 using VAR-GARCH and observed post-2008 feedback trading and volatility spillovers from stock returns to fund flows, though effects weakened during the crisis.
Bayar et al. (2022) examined 15 emerging markets from 2004 to 2019, which showed that stock market development significantly affects pension funds and insurance in the short-term, while pension funds positively influence stock markets in Brazil, Chile, Hungary, Mexico, Peru, and South Africa in the long-term. Sanusi and Eita (2022) analyzed South Africa from 1990 to 2022 using asymmetric cointegration and reported long-run correlations between pension fund investments and stock market variables, suggesting that secure pension funds can strengthen market depth. Bissoondoyal-Bheenick et al. (2023) observed that, over the period 1990–2016, investment risk increases as portfolios shift from moderate to more aggressive options, while balanced fund allocations do not influence long-term risk. Morina and Grima (2022) found that pension fund investments in global financial markets positively contribute to economic growth in non-OECD countries from 2002 to 2018.
Assefuah et al. (2023) examined 48 African countries using system generalized method of moments (GMM) and found that pension fund interactions negatively affect capital market development, recommending cross-listing, cross-border investment, and alternative asset allocation. Heusel and Mager (2023) studied corporate pension plan funding from 2000 to 2017 and found that lower funding levels are associated with higher unexpected earnings and stock returns, with weaker underreaction for firms with greater investor attention and transparency. Hwang and Cho (2023) analyzed the Korean stock market from 2002 to 2018 using multivariate regression, demonstrating that a 1% increase in pension fund activity raises the market by 0.168%, with trades of different investor types positively affecting newly added stock returns, indicating that pension fund trading influences index inclusion effects.
Methodology
This article quantitatively analyzes the role of pension fund investments in shaping South African stock market volatility from 2010Q1 to 2022Q4 (Table 1). To estimate volatility, the study employs generalized autoregressive conditional heteroskedasticity (GARCH), asymmetric power autoregressive conditional heteroskedasticity (APARCH), and nonlinear power autoregressive conditional heteroskedasticity (N-PARCH) models, which capture key features of financial time series, including volatility clustering, persistence, and asymmetry (Chinhamu & Chifurira, 2019; Engle, 1982; Jeribi & Ghorbel, 2021; Xiao & Koenker, 2009). APARCH and N-PARCH account for asymmetric responses to positive and negative shocks, while N-PARCH further incorporates nonlinearities, capturing complex patterns and interactions in volatility dynamics. These models enhance the accuracy of volatility estimation and forecasting. Similar approaches have been used by Babalos et al. (2021) and Aggarwal et al. (2021).
Economic Variables of the Study.
The article uses a MSDR model to assess pension funds’ impact on stock returns and volatility across regimes. MSDR model captures shifts in relationships under varying market conditions, including stable or volatile periods (Hansen, 1996). Similar applications appear in Coşkun et al. (2017) and De la Torre-Torres et al. (2018).
Theoretical Framework and Model Specification
The article used the framework for stock exchange transactions, expressed in Equation (1).
Here,
Factor-based models can include multivariate ARCH models. Stock exchange volatility is estimated as
Model Specification Autoregressive Conditional Heteroskedasticity and Other Models
Research on volatility modeling highlights that the ARCH(p) model, introduced by Engle (1982), captures the effect of past volatility on current and future conditional variance as represented in Equations (6)–(8).
where,
where
where
where
where
Model Specification Markov-Switching Dynamic Regression Model
In a MSDR, the series moves between different hidden regimes according to a Markov process, with the time spent in each regime varying randomly. This framework allows the behavior of the series to adapt depending on the regime it is in, capturing changes in dynamics over time (Hansen, 1996, 2000). If given an economic data series denoted by
Equations (14) and (15) present the Markov-switching autoregressive model with constant and time-varying transition probabilities, respectively, allowing regime shifts over time. In Equation (15),
In this specification,
The subscript
The parameter of interest,
The transition probabilities
This mechanism governs the evolution of the Markov chain by determining the probability of transitioning between regimes over time. The MSDR framework, which captures regime-dependent dynamics, is formally specified in Equations (23)–(25). In addition, Equations (1)–(5) establish the core theoretical structure of the model. These equations are subsequently extended and embedded within the Markov-switching framework, allowing the baseline relationships to vary across regimes and thereby providing a more flexible representation of the underlying economic dynamics.
Results
Appendix Table A1 (available online as supplemental material) presents the descriptive statistics of the main variables. Inflation expectations
The correlation analysis in Appendix Table A2 (in supplemental material) reveals several economically meaningful relationships. Inflation expectations are negatively correlated with stock market volatility −0.347, suggesting that higher expected inflation may introduce uncertainty in financial markets, consistent with empirical evidence that rising inflation expectations often elevate risk perceptions and market volatility (Andersen et al., 2003; Bekaert & Wang, 2010). GDP growth shows a positive correlation of 0.338 with volatility, indicating that periods of stronger economic expansion may coincide with heightened financial market fluctuations, potentially due to adjustments in monetary policy or investor repositioning, which aligns with findings by Campbell et al. (2001). The World Uncertainty Index positively correlates with volatility (0.34), confirming that macroeconomic and geopolitical uncertainty amplifies stock market fluctuations, as documented by Ahir et al. (2022). Pension fund variables exhibit exceptionally strong positive correlations with volatility: withdrawals
Appendix Table A3 (in supplemental material) presents the Dickey–Fuller (DF) unit root test results for the key macroeconomic, financial, and public finance variables used in the study. The test was applied to the second-differenced series

Figure 1 shows clustering of economic variables into the first and second volatility waves. Graphs (a) and (b) indicate that volatility in the first wave persists into the second, suggesting clustering. Such patterns are effectively modeled using ARCH models, which capture time-varying volatility. Graphs c–d show the data approximate a normal distribution, supporting the use of ARCH models for accurate volatility estimation and prediction.
Autoregressive Conditional Heteroskedasticity (ARCH) Effect Test.
Table 2 reports White’s and Breusch–Pagan tests for heteroskedasticity and ARCH effects. White’s test prob > χ² = 0.0282 and Breusch–Pagan prob > χ² = 0.0028 indicate volatility clustering, where high-volatility periods tend to follow high-volatility periods, and low-volatility periods follow low-volatility periods. Figure 2 shows the conditional variance of
Before estimating the conditional variance for the GARCH family models, the appropriate mean equation for the stock exchange series
Appendix Table A5 (in supplemental material) reports the estimation results for GARCH(1,1), APARCH, and N-PARCH models applied to JSE secondary market transactions

Table 3, the stock exchange in regimes 1 and 2, where estimation 1 reflects the impact of
The Stock Exchange in Regimes 1 and 2.
Appendix Table A6 (in supplemental material) reports the impact of pension fund activity on stock market volatility across regime 1 (lower-volatility periods) using GARCH, APARCH, and N-PARCH models. Pension fund withdrawals
Employer contributions
Member contributions
Figure 3 presents the regime 1-to-2 transition probabilities for

Figure 4 shows regime 1-to-2 transition probabilities for stock exchange rate volatility. Regime 1 has a mean volatility of 24.91%, while regime 2 has 45.66%. The shift between regimes highlights the dynamic nature of market risk. In low-volatility regime 1, investors may favor stable returns, whereas in high-volatility regime 2, strategies that account for greater uncertainty, such as diversification or hedging, are required. Understanding these transitions is essential for investors, policymakers, and regulators to manage risk and maintain market stability.

Table 4 reports the expected duration of each regime for
Expected Duration to Stay in the Regime
Number of observations = 48
Table 5 reflects the matrix of transition probabilities of
Matrix of Transition Probabilities.
Number of observations = 48
Conclusion
This study examined the relationship between pension fund activities, specifically withdrawals and contributions, and stock market performance in South Africa. It addresses a critical gap in the literature regarding the dynamic impact of pension fund flows on stock market returns and volatility under different market regimes, providing nuanced insights into investor behavior and market stability. The research question focused on how pension fund withdrawals and contributions influence stock market returns and volatility, and whether these effects vary across distinct market conditions.
The empirical analysis reveals several key findings. First, both pension fund withdrawals and contributions significantly affect stock market returns. Higher withdrawals are positively associated with returns across both regimes, highlighting the importance of participant behavior in shaping market outcomes. Similarly, contributions from both individuals and employers are positively linked to returns, suggesting that inflows into pension funds can reinforce stock market performance. Second, the study uncovers regime-dependent effects on volatility. In regime 1, withdrawals reduce volatility, implying a stabilizing effect, possibly due to counter-cyclical investment behavior during periods of market distress. Conversely, in regime 2, withdrawals increase volatility, reflecting liquidity pressures and market imbalances from excessive outflows. Employer contributions exhibit a similar pattern: they decrease volatility in regime 1 but increase it in regime 2, highlighting the role of market conditions and investor sentiment in mediating the impact of pension fund flows.
These findings have both theoretical and policy implications. Theoretically, the study contributes to the literature on institutional investors by demonstrating that pension fund activities can have dual effects on market stability depending on prevailing market regimes. This reinforces the need to consider nonlinearities and behavioral responses in modeling the relationship between institutional flows and market dynamics. From a policy perspective, regulators and policymakers should develop mechanisms to guide withdrawal and contribution behavior to align with market conditions. Measures could include monitoring excessive fund outflows, establishing risk-based withdrawal guidelines, and promoting investor education to mitigate volatility shocks. Pension fund managers and financial advisors play a crucial role in equipping participants with knowledge about the potential market impact of their actions, thus enhancing overall financial stability.
This study is subject to certain limitations. The analysis relies on available market and pension fund data, which may not fully capture informal or unreported flows. The regime classification assumes stability over the examined periods, which may not account for abrupt market changes outside the identified regimes. Additionally, the findings are specific to South Africa, and generalization to other emerging markets should be made cautiously. Future research could expand the analysis by incorporating high-frequency data, enabling a more precise examination of short-term market responses to pension fund activities. Investigating the interaction between pension fund flows and other institutional investors, such as mutual funds and hedge funds, could further illuminate market dynamics. Moreover, exploring behavioral factors influencing participant decisions, such as risk perception and financial literacy, would provide a deeper understanding of the mechanisms driving the observed effects.
Footnotes
Data Availability Statement
The data that support the findings of this study are derived from publicly available sources. These data are available from the corresponding author upon reasonable request.
Declaration of Conflicting Interests
The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author received no financial support for the research, authorship, and/or publication of this article.
