Fitch Ratings has upgraded MTN to an "AA-", with a stable outlook.
This news comes ahead of an expected announcement this weekend regarding a possible buy-in by Indian telecommunications company Reliance Communications.
The two companies are locked in exclusive talks, there period of exclusivity for which expires on Tuesday 8 July. Speculation is rife, however, that some kind of deal will be announced this weekend.
While neither company is commenting about the negotiations it is widely expected that Reliance will make an offer for up to 51% of MTN instead of the full merger initially anticipated.
In terms of a share swap, Reliance could end up as the majority shareholder in MTN, while itself becoming a subsidiary of MTN. The number of shares changing hands could be anything from 35% to 51%.