Found it: they withdrew for "business reasons". Read below:
Business Reasons: under certain circumstances, MIS will withdraw a Credit Rating for a Rated Entity or an obligation for reasons unrelated to the situations identified above. When MIS indicates that a Credit Rating was withdrawn for “business reasons,” this refers to MIS’s business reasons, not the business reasons of the Rated Entity or obligor. MIS’s business reasons generally do not reflect any concerns about the Rated
Entity’s creditworthiness or the quality of its management. MIS’s decision to withdraw a rating under these circumstances will attempt to balance the informational benefit to market participants from maintaining a Credit Rating against the resources required to maintain and monitor that Credit Rating or other business considerations.