Brusov P.N.Doctor of Physical and Mathematical Sciences, Professor of department "Applied Mathematics", the Financial University under the Government of the Russian Federation pnb1983@yahoo.com
Filatova T.V.PhD in Economics, Professor of department "Financial management", the Financial University under the Government of the Russian Federation mfilatova@fa.ru
Dolgov D.M.Student of department "Financial management", the Financial University under the Government of the Russian Federation infoddisney@gmail.com
Qualitatively new effect in corporate finance is found: reduction of cost of own capital with leverage growth. In the article complete research of effect within Brusov-Filatova-Orekhova theory is carried out. At some ratios between cost of loan and share capital the open effect takes place at the rates of a profit tax existing in the western countries and Russia that provides its practical value.
Keywords: tax, cost, structure, capital, leverage, Modigliani-Miller's theory, Brusov-Filatova-Orekhova theory