Dec. 22, 2020 8:00 am ET A Goldman Sachs Group Inc. unit that buys stakes in alternative investment managers has made its latest push into the real-estate industry by investing in a firm that acquires stores, warehouses and other properties from big companies and then leases them back. The unit, Petershill, in November purchased a minority stake in Oak Street Real Estate Capital LLC, which has raised over $6.5 billion since launching in 2009. Oak Street’s funds have purchased hundreds of stores, warehouses and office buildings sold and leased back by companies such as Walgreens Boots Alliance Inc. and Big Lots Inc. The size of the stake and the price paid by Goldman weren’t disclosed, but the deal valued Oak Street at $2 billion, according to people familiar with the matter.