* Extend talks by a month; Bharti seen sweetening offer
* Bharti, MTN say terms may be adjusted
* Combined firm would be world's third-biggest telecoms firm
* To have 200 mln clients across India, Africa & Middle East
* Bharti, MTN shares underperform strong broader markets (Adds more comments, updates shares)
By Devidutta Tripathy and Gugulakhe Lourie
NEW DELHI/JOHANNESBURG, Aug 3 (Reuters) - India's Bharti Airtel and South Africa's MTN Group extended exclusive talks aimed at creating the world's No. 3 mobile operator, setting the stage for a sweetened deal for MTN shareholders.
Bharti and MTN, which have held talks for over two months for a proposed $23 billion complex cash and share swap deal, said on Monday the structure and terms of the potential transaction may be adjusted.
Some MTN shareholders including the main Public Investment Corporation (PIC) are holding out for a higher price, as they feel Bharti needs to pay a bigger premium for effective control of MTN.
"If there was no deal to be done they would have canned it. What's significant is that the deal is not off," said Jan Meintjes, a telecoms analyst at Cape Town-based Gryphon Asset Management, which owns shares in a MTN.
"I still maintain they need to improve the terms of the deal for MTN minorities," he said.
Under the initial terms, MTN and its shareholders would take 36 percent economic interest in Bharti and the Indian firm would end up with 49 percent of MTN.
The companies would eventually go for a full merger creating an emerging markets giant with more than 200 million customers criss crossing 23 countries across the Indian sub-continent, Africa and the Middle East.
A combined entity would be the third-biggest mobile operator based on subscribers, behind China Mobile and Vodafone, although its annual sales of $20 billion would be dwarfed by China Mobile's $60 billion and Vodafone's $65 billion.
The exclusive talks over the deal, which would see Bharti and MTN pay cash and stock for a stake in the other, were due to end on July 31. The talks have been been extended to Aug. 31.
"As discussions between the parties regarding the potential transaction are continuing, both parties have agreed to extend the exclusivity period," Bharti Airtel said in a statement.
Akhil Gupta, a director at Bharti Airtel, told ET Now television he hoped this would be the last deadline extension, but declined to comment on a possibility of a revision in terms.
SECOND TIME LUCKY?
Bharti and MTN revived merger negotiations in May, a year after previous talks broke down over who would control a merged entity. MTN had held talks with Bharti's rival Reliance Communications in May 2008, but these also failed.
"This is the first clear indication from Bharti that the price could be increased and deal may not be in the same form," said Sanjay Chawla, a telecom analyst with Mumbai-based brokerage Anand Rathi Financial Services.
"They have room to increase the stock part under India FDI (foreign direct investment) rules. But MTN may ask for raising the cash too. It may well end up as a change in both," he said.
Bharti's shares, valued at about $32 billion, ended steady in a Mumbai market up 1.6 percent, after the stock earlier rose as much as 1.7 percent. MTN shares rose 0.2 percent, but underperformed a 1.9 percent gain in the JSE Top-40 index.
KEY AFRICAN MARKET
Analysts say Africa being the last of less-penetrated markets in terms of mobile growth presents a big opportunity for global mobile firms, who are seeing cut-rate competition in saturated markets and are facing falling call tariffs.
The deal would give both Bharti and MTN access to new markets ripe for growth, while a full merger would yield cost savings, allow for technology sharing, and provide the financial muscle for more expansion, analysts said.
India's stock market regulator has said MTN and its shareholders can buy 36 percent in Bharti via global depositary receipts without triggering a mandatory open offer, while the foreign shareholding in Bharti should not breach a 74 percent sectoral cap.
South Africa's government, keen to calm investors after its union allies almost sank a deal by Vodafone in May, is unlikely to block the Bharti-MTN deal.
But the complex deal would take time as some MTN shareholders want Bharti to pay more.
"At this stage, there is not much clarity. But a sweetened offer cannot be ruled out as some MTN shareholders want Bharti to pay more," said R.K. Gupta, managing director at New Delhi-based Taurus Asset Management.
Standard Chartered was advising Bharti Airtel, while Bank of America Merrill Lynch and Deutsche Bank were advising MTN. ($1=47.8 rupees=7.763 rand) (Additional reporting by Narayanan Somasundaram, Sumeet Chatterjee and C.J. Kuncheria in India; Editing by Ranjit Gangadharan and Anshuman Daga)