(Bloomberg) -- Wintershall Dea GmbH, an energy venture between chemicals group BASF SE and billionaire Mikhail Fridman, is exploring the sale of its stake in a company running some of Germany’s crucial gas pipelines, people with knowledge of the matter said. 

The oil and gas explorer is working with an adviser to gauge buyer interest in its 50% stake in WIGA, a holding company that operates a more than 4,000 kilometer pipeline network through Germany linking five European countries, according to the people. 

WIGA runs the pipelines through its Gascade, Opal and NEL transportation subsidiaries. Its assets are valued at more than €5 billion ($5.4 billion) including debt, the people said. 

Wintershall Dea has already held preliminary discussions about a deal with some infrastructure investors, which are keen to secure assets offering predictable returns, the people said, asking not to be identified discussing confidential information. 

Deliberations are ongoing and there’s no certainty they’ll result in a transaction, they said. A representative for Wintershall Dea declined to comment. 

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Created in 2019 through the merger of Germany-based BASF’s energy unit and a division of Fridman’s investment company LetterOne Holdings SA, Wintershall Dea was valued at more than $20 billion before the Covid-19 pandemic. It’s among a handful of independent European oil and gas firms considering going public, but has seen its plans for an initial public offering frustrated in recent years.

Germany’s gas giant Uniper SE is separately exploring a sale of its 20% stake in WIGA subsidiary Opal. When the German government nationalized Uniper last year, conditions imposed by the European Commission included asking the company to finalize the Opal stake sale by the end of 2026 at the latest.

Opal and NEL used to transport gas arriving via the Nord Stream pipeline from Russia. The pipeline was damaged in explosions last year, which caused Wintershall Dea to write off its Nord Stream 2 financing of around €1 billion.

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--With assistance from Anna Shiryaevskaya and Petra Sorge.

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