[5] He is credited for initiating the diversification of Motor Oil Hellas, by launching activities in the renewable energy sources sector.
As a result, in May 2024 the stock of Motor Oil Hellas reached an all-time high, bringing the valuation of the company to EUR 3 billion.
In 2018, he initiated the project for the transformation of the Investment Bank of Greece (IBG),[12] which in the meantime had been acquired by Motor Oil Hellas.
IBG was renamed to Optima Bank and listed on Athens Stock Exchange on 4 October 2023 and joined FTSE25 index on 23 December 2024.
[18] On 22 April 2008, he announced the decision of the Vardinoyannis family to reduce their share in Panathinaikos Football Club to 50%[19] – after 30 years of full ownership – through an €80 million increase of the company's capital stock.
After the negotiations and the share capital increase, the family would hold 56% of the club, Panathinaikos Athlitikos Omilos 10% and the rest of the shareholders 34%.
In February 2015, Vardinoyannis said in a statement to Reuters that the new Prime Minister of Greece Alexis Tsipras had a valid point in attacking corrupt Greek oligarchs.