MTNL Mahanagar Telephone Nigam Ltd Credit Rating Changes Announcement 2025 - Rating Rationale Disclosure CRISIL issues rating rationale for MTNL bonds, maintaining AAA (CE) with Watch Negative; rationale attached for SEBI LODR disclosure..Find Corporate Announcements for Press Releases, AGM, Insider Trading & SAST, Results and Corporate Action for Mahanagar Telephone Nigam Ltd