Helsinki -- 31 May 2017 is the last effective date for substances imported or produced at more than 1 tonne/year can be registered under the EU's REACH programme has been announced by the European Chemicals Agency (ECHA)
The ECHA said pre-registration is only obligatory if companies want to benefit from the extended registration deadlines. Companies can also decide to register their phase-in substances immediately, but in this case it is necessary to first submit an inquiry.
After pre-registration and subsequent discussions on the sameness of the substance, the company becomes a member of a Substance Information Exchange Forum (SIEF). SIEFs are cooperatives where multiple producers of a substance can work together to try to get it approved for use under REACH regulations.
There are more details of the process here.