During the nineteenth and early twentieth centuries, western European countries introduced general incorporation and additional flexible enterprise forms, but the Russian Empire left its concession system of incorporation in place. The Empire's only major corporation reform, the 1901 law, strengthened minority shareholder rights and removed bankers from boards of directors for certain corporations. The reform offers a rare opportunity to examine the financial effects of improving corporations’ principal–agent relationships through regulation, because the reform did not affect all corporations equally. Corporations affected by the reform had smaller total share capital, fewer shares, and higher par values for shares as observed in 1905. The new regulations may have increased the cost of having shareholders and hence disciplined corporations’ founders to be more conservative in raising capital by issuing stock. Removing bankers from boards of directors may have removed an important source of firms’ founding capital, though corporations could easily evade this provision. The results also show that, although the commercial code treated all corporations equally, there were two major groups of Russian corporations that behaved differently, and, despite the fact that corporate charters could grant individual exceptions to the commercial code, a revision in the commercial code changed corporations’ behaviour.