1. Penguin Random House: This is the largest book publishing company in the world, formed by the merger of Penguin Group and Random House in 2013. Penguin Random House owns numerous imprints and publishing divisions, including Penguin Classics, Random House, Crown, Knopf Doubleday, and many others.
2. Hachette Livre: Hachette Livre is a French-based multinational publishing group and one of the "big five" publishers globally. It owns imprints such as Hachette Book Group, Little, Brown and Company, Grand Central Publishing, Orion Publishing Group, and many more.
3. HarperCollins Publishers: HarperCollins is another major publishing conglomerate, owned by News Corp. It includes imprints such as Harper, HarperCollins, William Morrow, Avon Books, and many others.
4. Simon & Schuster: Simon & Schuster is a renowned publishing house owned by ViacomCBS. It consists of imprints like Simon & Schuster, Atria Books, Scribner, Gallery Books, and more.
5. Scholastic Corporation: Scholastic is known primarily for its children's and educational books. It owns imprints such as Scholastic Press, Arthur A. Levine Books, Orchard Books, and various others.
These ownership chains represent some of the largest players in the book publishing industry, each with their own extensive lists of imprints and publications.