Objectives: The purpose of this study is to investigate the role of company ownership in investment efficiency, focusing on business strategy.

Design/methodology/approach: This research is applied, with a causal correlation methodology. The statistical population of the study included all firms listed on the Tehran Stock Exchange. Using a systematic sampling method, 135 companies were selected as the sample and examined over an 8-year period from 2015 to 2022. Three types of institutional ownership—management, family ownership—were considered.

Results: The results of testing the research hypotheses indicated that institutional ownership, as well as family ownership, have a direct and significant relationship with the investment efficiency of the company. However, managerial ownership showed no relationship with the efficiency of the company's investment. The interaction of family ownership with business strategy impacted investment efficiency. However, the interaction of institutional ownership and managerial ownership with business strategy did not affect the efficiency of the company's investment.

Innovation: The current research provides evidence that the types of company ownership have an impact on investment efficiency and emphasizes that the role of business strategy cannot be overlooked.