Italy's Eni and Norway's HitecVision completed the sale of a 5% stake in Norwegian oil firm Vaar Energi worth $530 million, the Italian energy group said on June 9.

Vaar, whose shares dropped 9% in morning trade, listed in February and was the largest dedicated oil E&P company to list globally in almost a decade.

Since the initial public offering, which valued the group at 69.9 billion Norwegian crowns ($7.37 billion), its Oslo-listed shares have climbed by about 50%.

"The excellent trend in the share performance of Vaar Energi... has unlocked the opportunity to place on the market additional shares thus increasing the liquidity on the stock and further consolidating and expanding the shareholder base of institutional investors," Eni CFO Francesco Gattei said in a statement.

Eni and investment firm HitecVision sold respectively a 1.2% and 3.8% stake in Vaar Energi, through an accelerated book-building process, for 40.2 Norwegian crowns per share.

After the placement, the free float of Vaar increased to around 16.2% from 11.2%. Eni's stake in Vaar was 63.1% and HitecVision held 20.8%.