* Mobile operator to list 25 percent stake
* To offer shares in London and Kazakhstan
* Credit Suisse and UBS appointed to run sale (Updates with sources, adds background)
LONDON/MOSCOW, Nov 5 (Reuters) - Kcell, Kazakhstan's biggest mobile operator, plans to list in Kazakhstan and London by the end of the year and has appointed banks to run the process, sources close to the deal said.
Nordic telecoms group TeliaSonera agreed last year to buy a 49 percent stake in Kcell for $1.52 billion and said it planned to float a quarter of the company's shares.
Kcell could begin marketing the initial public offering (IPO) next week, one of the sources said on Monday, while another said it was aiming for a market debut in December. A third source said it could list before the end of the year.
The offering could compete for investor attention with Russia's second biggest mobile operator MegaFon, which has delayed a planned London listing until after its third-quarter financial results, due in early November.
It is possible MegaFon's sale could still be held back until January however, IFR, a Thomson Reuters publication, reported last week, citing bankers involved in the deal.
Credit Suisse and UBS are advising on Kcell's planned offering, two of the sources said.
Kazakh investment bank Visor Capital is also working on the listing, the Kazakhstan Stock Exchange said in a statement, confirming that Kcell had made an application to list its shares on the local stock market.
Visor Capital and Kcell both declined to comment.
The sources did not say how much the company hoped to raise from the sale, but the Financial Times reported it was seeking as much as 500 million pounds ($802 million).
This would be around the level the company was valued at when TeliaSonera, which also owns a minority stake in MegaFon, bought its 49 percent stake.
While European telecoms stocks have fallen in value this year, with the European telecom index down about 7.2 percent year-to-date, emerging market-focussed telecoms companies have fared better.
New-York listed Russian providers Vimpelcom and MTS have seen their shares rise around 16 percent and 15 percent respectively since the start of the year.
Kcell, the leading mobile operator in Kazakhstan by market share in terms of revenue and subscribers, had 12.7 million subscribers at the end of the third quarter.
A spokeswoman for TeliaSonera referred Reuters to its third quarter statement that preparations for a public listing of Kcell were continuing and declined to comment further.
($1 = 0.6235 pound) (Additional reporting by Robin Paxton in Almaty, Simon Johnson in Stockholm, Leila Abboud in Paris and Natalie Huet in London; Editing by Marguerita Choy and Mark Potter)