Prime Registry is appearing to be a one stop shop for MIPs/MACRA submission/Attestation.
They started with the distinct capability to be able to submit on the MIPS quality measure.
They are rolling out updates now due to go live in November 2017 to offer submission/attestation capability for ACI ( Advancing Care Information) and IM ( Improvement activities, the other two measures of MIPS/MACRA for 2017.
CMS website is already in place for submission/attestation for ACI measures and are planning to add capability to accept IA measures. So that option is there but Prime registry will allow to roll it all up from one site.
Thanks
Aramiz