UPDATE 1-Onexim sells entire Polyus stake for $3.6 bln

* Deal was under review by UK Takeover Panel

* Retailer Mutsoyev buys 18.5 pct

* Fruit juice magnate Yushvayev buys 19.3 pct

* Speculation of Polyus-Polymetal merger

MOSCOW, Feb 22 (Reuters) - Russian billionaire Mikhail Prokhorov's Onexim group has sold its entire 37.78 percent stake in London-listed gold miner Polyus Gold for $3.6 billion to two Russian buyers.

Onexim said on Friday it had sold an 18.5 percent stake in Russia's largest gold miner to Zelimkhan Mutsoyev for $1.77 billion, and 19.28 percent to Gavriil Yushvayev for $1.85 billion.

Polyus shares closed at 219 pence on Thursday, valuing the stake at $3.8 billion, according to Reuters data.

The deal had been under review by the UK Takeover Panel over whether retail tycoon Mutsoyev and fruit juice magnate Yushvayev were acting in concert.

If the pair had been found to form a 'concert party' together, or in relation to existing shareholder Suleiman Kerimov, who owns 40 percent of Polyus, the deal would have triggered a mandatory buyout to minority shareholders.

The sale puts paid to ambitions for an international merger harboured by Prokhorov, the investor-turned-politician who ran for the presidency last year and now leads a small liberal political party in Russia.

There has been high industry interest in the Polyus deal, due to speculation that it could pave the way for a tie-up with Russian peer Polymetal, a company formerly owned by Kerimov, that would create a business worth $17 billion.

A merged company could also be first in line to develop the country's untapped deposits such as Siberia's Sukhoi Log, one of the world's largest virgin gold deposits which is likely to be put up for tender soon.