* Analysts concerned by "missing" treasury stock
* IFRS earnings down, diverge from Russian accounts
* Ordinary, preferred shares fall 3 pct (Adds ownership details, analyst comment)
By Vladimir Soldatkin
MOSCOW, April 30 (Reuters) - Russia's third-biggest oil firm Surgutneftegas revealed a $29 billion cash pile, as it reported annual results to International Financial Reporting Standards for the first time in more than 10 years.
But the company, still headed by Soviet-era "red director" Vladimir Bogdanov, left analysts at a loss over its ownership structure after disclosing that it held just 650,000 shares in treasury.
That is down from 17.6 billion treasury shares, or a 40 percent stake worth $15 billion, disclosed in Surgut's last results to an internationally recognised reporting standard in 2001.
"We are waiting for the company to tell us where these shares have gone," said Alexander Kornilov at Alfa Bank, ahead of a briefing for analysts. Surgut was required to publish IFRS results under a new law.
Management was long believed by analysts to have controlled around 90 percent of Surgut through an evolving structure of affiliates - including the in-house pension fund - but has never fully disclosed the company's ownership.
The company's balance sheet revealed that it held 549 billion roubles in liquid assets. That is an exceptionally high figure for the oil industry - a cash-generative business that typically relies on debt to maximise balance-sheet efficiency.
Of its 898 billion roubles in short- and long-term deposits, the lion's share was held at state-controlled Sberbank , with further tranches at the Russian unit of Unicredit, Gazprombank and VTB.
The deposits earned a rate of interest of just 3 percent last year, begging questions over whether it would be better to invest the money or return it to shareholders, including holders of Surgut's high-yielding preferred stock.
Analysts also expressed concern that Surgut's IFRS earnings for 2012, which fell by 34 percent to 180 billion roubles, diverged from the figure of 161 billion roubles the company previously disclosed to Russian Accounting Standards.
Surgut ordinary and preferred shares were weaker in volatile trading, with both showing losses in Moscow trading of around 3 percent at 0730 GMT.
Surgut's 2012 profit decline was driven by a one-off gain in the previous year from the 1.88 billion euro ($2.5 billion) sale of a minority stake in Hungarian energy group MOL to the country's government. ($1 = 30.9212 Russian roubles) ($1 = 0.7634 euros) (Additional reporting by Denis Pinchuk; Editing by Douglas Busvine and Helen Massy-Beresford)