Blackstone — the world’s largest “alternative investment” company — recently closed on the biggest private real estate deal in history. It paid $18.7 billion for the US warehouse division of GLP, a global logistics firm based in Singapore.

Private equity firms like Blackstone, Apollo, and Carlyle have grown ever more powerful in the easy credit decade following the 2008–2010 financial crisis. This isn’t good news. The relationship between private equity firms and ordinary folks is zero sum: when PE firms thrive, working families and communities suffer.

Here are five things you should know about private equity firms.