FACTBOX-Key facts about SAfrica's MTN, India's Bharti

Sept 30 (Reuters) - South Africa's MTN Group (MTNJ.J) and India's Bharti Airtel Ltd (BRTI.BO) have been in politically charged talks since May 25 over a $24 billion tie-up to create the world's third-biggest mobile operator by subscribers.

Following are key facts about the two companies:

BHARTI AIRTEL (BRTI.BO)

* After starting with a licence to launch a mobile network in New Delhi in 1995, Bharti Airtel is now the largest telecoms operator in the world's second-biggest and fastest-growing mobile market by subscribers.

* At end-July, Bharti had 105.2 million mobile subscribers, or nearly a quarter of the total Indian mobile user base of 427.3 million. Bharti added 19.5 million users in the seven months to July, from a market total of 80.4 million new users.

* Still, less than 40 percent of India's billion-plus population have mobile phones and research firm Gartner forecast mobile subscribers in the country to reach 771 million by 2013.

* India has 11 mobile operators, spanning its 22 telecoms service areas. Key Bharti competitors include Reliance Communications (RLCM.BO), Vodafone Essar (VOD.L), state-run Bharat Sanchar Nigam, Idea Cellular (IDEA.BO) and Tata Teleservices. At least four new firms, including local units of international firms Telenor (TEL.OL) and Etisalat ETEL.AD are likely to start mobile services in India by the end of 2009.

* Local call tariffs in India now average about 2 U.S. cents a minute, down from more than 30 U.S. cents earlier this decade, which has helped to fuel growth.

* Increased competition among operators has put further pressure on tariffs, with average revenue per user (ARPU), a key metric in telecoms, on a continuous downward spiral.

* Bharti, however, has bet on building a "minutes factory" -- which would allow people to talk more when tariffs are low -- and said it wants to replicate this low-tariff model after an emerging market acquisition.

MTN GROUP (MTNJ.J)

* Created in 1994, at the end of apartheid, in 1997 the company embarked on an international expansion drive, acquiring licences in Uganda, Rwanda and Swaziland, before starting operations in these countries the following year.

* In 2005, MTN started operations in Nigeria and in 2006 it bought Dubai-based Investcom for $5.5 billion, bolstering its Middle Eastern and African presence and bringing its operations to 21 countries.

* MTN has said it aims to be the leading emerging markets telecom. At end-June, MTN had 103 million total subscribers, driven by robust growth in MTN Nigeria and MTN Irancell. MTN mostly occupies the No.1 or 2 market positions in its 21 markets.

* Mobile penetration in its markets is, on average, below 50 percent of the population. MTN estimates that the addressable mobile telephony market in its present footprint will grow to over 381 million in the next five years, from 220 million now.

* MTN's major competitors are Vodacom (VODJ.J), the South African mobile operator in which Vodafone (VOD.L) holds a majority stake, and Kuwait's largest mobile operator, Mobile Telecommunications Co (ZAIN.KW).

* In 1996 MTN was the first mobile operator to introduce a prepaid cellular service, popularising "pay as you go" in emerging markets. In 2008, MTN introduced MTN Zone in nine markets, which encourages calls during low usage times by offering discounts of up to 95 percent on call rates.

* During 2008, competition intensified in virtually all MTN's markets with the entry of new operators, and it expects more competition to emerge in Uganda and Swaziland.

($1=7.671 Rand) (Sources: Thomson Reuters; Reuters News; Gartner; company websites) (Compiled by Gugulakhe Lourie and Devidutta Tripathy; editing by Simon Jessop)