i) preparing a monomer mixture in a monomer mixing stage by mixing bisphenol A, diphenyl carbonate and a beta catalyst in at least one monomer mixing device,

ii) preparing a carbonate oligomer in an oligomerization stage by reacting said monomer mixture in at least one oligomerization reactor,

wherein an alpha catalyst is added to the first of said at least one oligomerization reactors, said alpha catalyst being an alkali metal compound, an alkaline earth metal compound or a combination thereof,

iii) preparing the polycarbonate in a polymerization stage by further reacting the carbonate oligomer of the oligomerization stage in at least one polymerization reactor, wherein,

an end-capping agent different from phenol and having a single phenolic hydroxy group is added to the monomer mixture in the monomer mixing stage and/or to at least one oligomerization reactor in the oligomerization stage.