Preparation of branched siloxane containing silicon unit (I) comprises converting the silane hydrogen contained in the polymer chain of polysiloxane in the presence of ammonium or metal carboxylate, as catalyst in the absence of hydroxyl functionalized organic compound. Preparation of branched siloxane containing silicon unit of formula (R-SiO 3 / 2) (I) comprises converting the silane hydrogen contained in the polymer chain of polysiloxane in the presence of ammonium or metal carboxylate, as catalyst in the absence of hydroxyl functionalized organic compound. R : an organic residue. An independent claim is included for the siloxane, obtained by the above method.