A court acquitted energy group OMV's chief executive Wolfgang Ruttenstorfer of insider trading on Thursday in a case prosecutors said had put Austria's reputation as a financial center under the spotlight.

Judge Claudia Moravec-Loidolt told a crowded courtroom after more than nine hours of hearings that evidence to suggest insider trading "in my opinion was not there."

Ruttenstorfer had denied any wrongdoing in a share purchase he made in 2009, shortly before OMV announced a divestment that sent its stock higher, and had insisted the stock he got in a long-term option scheme did not lend itself to insider deals.

"The ruling is more than satisfactory. It clearly confirms that we always acted correctly," Ruttenstorfer told journalists after the trial. He said the case had important consequences for listed Austrian companies.

"I myself have learnt that it is really difficult for a CEO to buy shares (in their own company)," he said, adding that it was important that business heads had a stake in the long-term future of their companies. "But as we see, this can lead to major problems. I am glad that in my case they are solved, but a broader discussion about this is unavoidable and correct," he said.

Prosecutor Michael Schoen said he would appeal the verdict. Ruttenstorfer had entered the courtroom on Thursday looking relaxed and smiling, shaking hands with journalists and making made jokes and smalltalk. He looked tired towards the end of the trial, holding his head in his hands and staring at the floor.

Chief executive of the Vienna-based oil and gas group since 2002, Ruttenstorfer had said before the trial prosecutors were under pressure to use the case to prove their ability to secure a conviction for insider trading.

Austria has convicted only one person for the crime, handing out a suspended sentence, according to financial watchdog FMA.

"We are also here today because this concerns the national and international reputation of Vienna's stock exchange," FMA official Andreas Kubicek had told the court.

OMV's supervisory board has backed Ruttenstorfer, whose peers at major Austrian companies took out full-page newspaper ads to complain about what they saw as an unfair prosecution.

Mol Stake
Ruttenstorfer's contract as CEO expires in March, the stock has mostly not reacted to developments in the months-long case.

Last August, the FMA asked state prosecutors to investigate 60-year-old Ruttenstorfer over the share deal that authorities say made him a €44,000 ($60,310) paper profit.

Ruttenstorfer bought €620,000 worth of OMV stock on March 23, 2009, more than doubling his holding to 40,030 shares.

A week later OMV sold its 21% stake in Hungarian refiner MOL to Russia's Surgutneftegaz for €1.4 billion, in a deal priced at almost twice MOL's share price at the time.

The probe also centered on an interview he gave to an Austrian magazine days before the divestment, in which he said OMV would hold on to the MOL stake that year. He has been fined €20,000 in that case for market manipulation.

Ruttenstorfer, also on the board of Swiss drugmaker Roche, has worked for a total of 31 years at OMV, the largest energy company operating in emerging Europe.

OMV has a market capitalization of about €9.5 billion, making it Austria's second-largest listed company behind Erste Group Bank.