* Oil output 352,600 bpd in quarter, up 11 pct on year
* Revenue rises 21 pct, EBITDA up by 26 pct
* Deals in Bashneft shares blocked due to investigation
* Moscow court upheld shares arrest
* Sistema says doesn't plan to sell Bashneft (Updates with court upholding injunction)
MOSCOW, Aug 27 (Reuters) - Bashneft, a mid-sized Russian oil producer, posted a 20 percent rise in net profit and its highest average daily oil production in 20 years for the second quarter, but its shares fell as its majority owner was barred from selling.
Bashneft had been considering listing up to $2 billion worth of shares in London as early as September.
But parent company Sistema, a conglomerate, has been restricted from selling shares in Bashneft due to an investigation.
On Wednesday a court in Moscow overturned an appeal by Sistema and upheld an injunction prohibiting it from selling Bashneft shares, according to reports in local news wires.
Both Bashneft and Sistema declined to comment on the ruling. Bashneft shares were down around 3.5 percent in Moscow.
Its oil production reached 4.37 million tonnes in the second quarter (352,600 barrels per day), up 11 percent compared with the same period last year and its highest output in 20 years, the company said.
"The solid set of numbers was primarily driven by the increase in oil products output. As expected, Bashneft showed upward dynamics across all three key financial parameters, revenue, EBITDA and net income," VTB Capital said in a note.
Net profit reached 15.9 billion roubles ($440 million) in the second quarter, with revenues up 21 percent at 163.2 billion roubles. Earnings before interest, taxation, depreciation and amortisation (EBITDA) rose 26 percent to 28.6 billion roubles.
Since Sistema became the majority shareholder in 2009, Bashneft has been showing one of the highest production growth rates among Russian oil companies thanks to advanced recovery techniques used at its mostly depleted deposits.
Russian business daily Vedomosti has reported that state-controlled Rosneft, Russia's biggest oil producer, was interested in buying Bashneft. Rosneft declined to comment.
Mikhail Shamolin, Sistema's chief executive officer, said on Wednesday that Sistema had not received any offers to sell Bashneft and did not plan to sell it, Interfax news agency reported.
Local media have also speculated that the restrictions on deals in Bashneft stock could be linked to elections of the leader of the Urals region of Bashkortostan due later this year. Sistema acquired the bulk of Bashneft shares from entities with connections to the former leader of Bashkortostan.
Sistema has said the restrictions are related to an investigation, which it is not party to "and with which the company plans to fully cooperate".
Bashneft said last month it would postpone a share sale in London, citing unfavourable market conditions.
Sistema directly owns almost 72 percent of Bashneft's voting rights and has an economic stake of 86.7 percent, including 12.6 percent which it owns through subsidiary Sistema-Invest. (1 US dollar = 36.1200 Russian rouble) (Reporting by Olesya Astakhova, Vladimir Soldatkin and Katya Golubkova; Editing by Maria Kiselyova and Jane Baird)