U.S. investment firm Apollo Global Management has joined the race to buy Uniper, Germany's largest importer of natural gas. Apollo made a non-binding offer, two people with direct knowledge told Reuters on Wednesday. Germany's Handelsblatt also reported Apollo's interest.

A non-binding offer is an early bid. It sets out a price range but does not commit the buyer.

Uniper's story goes back to the 2022 energy crisis. When Russian gas supplies were cut, the company nearly collapsed. Germany took it over in a €13.5 billion bailout. Since then, Berlin has gotten about €3.5 billion back from Uniper, including state aid paybacks and dividends.

Now the government wants to sell. It owns 99.12% of Uniper and plans to sell up to 74.12%. European Union rules require Germany to cut its stake to a blocking minority by 2028. That is a share big enough to veto major decisions.

A sale could value Uniper at around €10 billion, Reuters has reported. That would make it one of Europe's biggest utility deals this year.

Apollo faces a crowded field. Czech energy firm EPH, controlled by billionaire Daniel Kretinsky, has bid. So have Brookfield with Canada's CPPIB, and Norway's Equinor. A team of KKR and German utility RWE also bid, one source said. Indicative bids were due Sept. 21.

Energy supply is a security issue. War with Iran has disrupted fuel markets, and there have been attempts to sabotage power grids, Reuters noted. That is why Uniper's next owner is drawing close attention in Berlin.

There is another option. The government is also exploring selling shares to the public in a stock-market listing. Uniper's unions prefer that path. They fear a new owner could break the company up.

Bidders should learn in the coming weeks whether they move to the next round, a third person said. Apollo and Uniper declined to comment.

What we know: Apollo is among at least five bidders for a majority of Uniper.
What we don't: Whether Germany picks a buyer or a stock listing.