Purpose Considering the constraints on resources and the need for firms’ planning to avoid recession and underdevelopment, enhanced investment efficiency would promote the capital market attractiveness and increase the performance of capital market investment. Empowering these markets through investment efficiency requires to promote the flow of information disclosure to stakeholders to provide the greater coherence and integration of information, enhance equal decision-making capabilities and promote trust and confidence in the company. The present study aims to examine the impact of stakeholder relationship capability on investment efficiency through testing the mosaic theory. Design/methodology/approach In this study, two criteria (namely, the ratio of net fixed assets to total assets and investment level) were used to measure investment efficiency. Furthermore, meta-synthesis and Delphi analyses were adopted based on a five-point Likert scale to measure the development of stakeholder relationship capability. To collect the research data, the questionnaires were sent to 142 companies in 2019, of which 112 questionnaires were returned by the managers of the firms listed in Tehran Stock Exchange. To fit and test the research hypothesis, partial least squares analysis was used. Findings After confirming the fit of the model, the results revealed that the stakeholder relationship capability had a positive and significant effect on investment efficiency. Originality/value With regard to the mosaic theory, this finding confirms that the equity of information in reflecting news and knowledge among stakeholders can promote the role of the firm’s stakeholder relationship capability, thus enhancing the investment efficiency.