DONG Energy has enjoyed a successful stock market debut after completing a flotation which signalled strong investor interest in the Danish firm, whose interests include North Sea oil and gas fields and UK windfarms.

Shares in the firm rose around 10 per cent on the first day of trading on the Nasdaq Copenhagen exchange leaving it with a market capitalisation of 108 billion Danish crowns (£10bn) and Goldman Sachs sitting on a big gain on its investment in the firm.

The flotation was the biggest completed on a European stock market this year.

Dong listed after completing an initial public offering of shares at 235 crowns, in the upper half of the expected range.

Investors including Goldman Sachs and the Danish Government sold shares worth around 17bn crowns in total.

With the government hailing strong demand for shares among retail and professional investors, the IPO and first day’s trading appear to provide a vote of confidence in the prospects for the firm.

Claus Hjort Frederiksen, Danish minister of finance, said of the IPO: “It gives DONG Energy a solid foundation to retain and develop its position as one of the leading green energy companies in the world.”

Formed through the merger of six Danish firms in 2006, DONG has invested heavily in developing a portfolio of windfarms in Northern Europe with the avowed aim of leading the transformation to renewable energy.

The UK is a key market for DONG, which operates six windfarms off England.

The company is developing the Hornsea facility off Yorkshire, which it says will be the largest offshore windfarm in the world.

Announcing plans for the IPO last month, DONG Energy said it has a low cost oil and gas portfolio centred around three high-quality assets in the North Sea.

These include a 20 per cent stake in the giant Laggan Tormore development off Shetland, which Total brought onstream in February.

The flotation may renew controversy about the Danish Government’s decision to sell an 18 per cent stake in DONG Energy to funds run by Goldman Sachs investment bank for 8bn crowns in 2013.

The valuation of the holding has more than doubled since then. The funds sold shares worth 3.2bn crowns in the IPO. They were left with a 14.7 per cent holding in DONG Energy worth 16bn crowns at yesterday’s closing price of 258 crowns.

The Danish government has 50.5 per cent.

DONG said more than 36,000 new investors were allocated shares through the IPO.

Retail investors in Denmark have been allocated around 10 per cent of the offer shares, with the remainder going to Danish and international institutional investors.