PurposeThis paper examines the relationship between heterogeneous political connections and corporate overinvestment.Design/methodology/approachBased on a comprehensive Malaysian dataset of 834 publicly listed companies from 2000 to 2022, the authors employed multivariate ordinary least squares regression to test the relationship.FindingsDespite different types of political connections, the findings demonstrate a positive relationship between political connections and corporate overinvestment. In particular, the association is more profound in government-linked companies (GLCs) but weaker in firms that developed political ties through family members of ruling elites. Further analysis reveals that the “helping hand” effect is only observed in GLCs and firms with politically connected directors and businessmen, whereas the “grabbing hand” effect is observed among firms connected through board, businessmen, and family ties. Moreover, the relationship is more persistent among firms with politically connected directors and businessmen around the regime change.Research limitations/implicationsRegardless of the types of political connections, the findings show that politically connected firms tend to engage in rent-seeking through political patronage networks and high levels of government interference in resource allocation. Therefore, a more sophisticated monitoring system should be developed within the political patronage networks to reduce the likelihood of different types of political-business collusion. In terms of research limitations, the research design does not consider the influence of financial constraints and management efficiency. Future research could explore these facets to comprehensively understand the dynamics between political connections and corporate investment decisions.Practical implicationsThe evidence informs market participants about the relationship between heterogeneous political connections and corporate overinvestment, reinforcing previous findings that crony capitalism, political patronage, agency problems, and weak governance are well-entrenched in Malaysia’s emerging economy. The government should acknowledge these concerns by enacting anti-corruption campaigns and promoting a fair business environment. In the meantime, policymakers might redesign regulations and revise corporate governance frameworks to substantially reduce the value of political connections, thereby diminishing the bargaining power of politicians.Social implicationsAs corporate investment efficiency has a considerable impact on firm value, investment decisions that enhance firm value will increase share price and maximise shareholder value. Conversely, firms may damage shareholder value if they overinvest or undertake projects that do not yield sufficient. Hence, the findings of this study may assist investors in making more informed judgements, particularly by understanding different types of business-government relations, as political connections are one of the determinants of corporate overinvestment.Originality/valueThis study reveals that the degree to which overinvestment issues manifest within firms is influenced by the nature of the political connections those firms possess. This indicates that politically connected firms should not be regarded as a homogenous group of firms.