Johannesburg: South African mobile giant MTN Thursday got a boost with an upgrade from A+ to AA- by the Fitch Ratings Agency, but the silence on continuing talks with India's Reliance Communications has seen the company's share price see-sawing in recent weeks.

With less than a week to go on the 45-day talks' exclusivity agreement between MTN and Reliance Communications, MTN is still not saying anything about the proposed deal. Analysts have speculated that Reliance wants to buy out MTN.

There are now expectations in the market that MTN may extend the talks, increasing the uncertainty that has seen MTN shares going from its high of 165 rands three months ago, when there were rumours of an imminent deal with Bharti Airtel to, its current price of 118 rands.

After the Bharti talks fell through, the share price dropped to 140 rands.

MTN has also refused to comment in the wake of a letter last month to from Reliance Industries, led by Mukesh Ambani, the estranged elder brother of Anil Ambani, saying that under a family pact between them, his group had the first right of refusal to buy a controlling stake in Reliance Communications.

The Fitch upgrade has not made any significant difference to MTN's price, even though the agency said it reflected MTN's position as a telecommunications leader in emerging markets. A rider to the upgrade did mention that Fitch had taken note of the discussion between the management teams of MTN and Reliance, which could result in a review of MTN's grading.