No data, No market
A major part of REACH is the requirement for manufacturers or importers of substances to register them with a central European Chemicals Agency (ECHA) A registration package will be supported by a standard set of data on that substance. The amount of data required is proportionate to the amount of substance manufactured or supplied.
If you do not register your substances, then the data on them will not be available and as a result, you will no longer be able to manufacture or supply them legally, i.e. no data, no market!