MTNL Mahanagar Telephone Nigam Ltd Credit Rating Changes Announcement 2024 - Rating Review MTNL received a review of the rating of Bonds worth Rs. 6500.00 Crs from Brickwork Ratings India Pvt. Ltd..Find Corporate Announcements for Press Releases, AGM, Insider Trading & SAST, Results and Corporate Action for Mahanagar Telephone Nigam Ltd