We analyse the effects of different types and concentration of ownership on performance using a large population of firms in the Czech Republic after mass privatization. Specifications based on first‐differences combined with instrumental variables show that the performance effects of different types and concentration of ownership are limited when compared to earlier studies. Often, concentrated ownership has a positive effect, a finding that supports the agency theory. The positive effect of foreign ownership is detected primarily for majority ownership and for ownership by foreign industrial firms. The state as a holder of the golden share has a positive effect on employment and sometimes, also on output and profitability. Overall, our results highlight the benefits of strategic restructuring accompanied by an inflow of new capital and managerial culture.