Prologis, the world’s biggest warehouse owner, has launched a bid to buy Blackstone’s portfolio of logistics properties in what would be the largest ever private real estate deal, the Financial Times reported on Monday.

Prologis has made a non-binding offer of a little over 21 billion euros ($23.14 billion) for Mileway, according to the report, which cited people familiar with the matter.

Of 20 or so prospective buyers approached by Morgan Stanley, the bank managing the process, eight looked seriously at Mileway but only Prologis submitted a non-binding bid, the Financial Times reported.

Read more: Reuters