Summary List Placement Airbnb has dropped the paperwork for its initial public offering, and it's ripe with juicy details that a startup doesn't have to disclose but a public company does, such as which investors own the largest stakes. As is typical these days, Airbnb is using a two-tier structure where it sells Class A shares to the public, with each of those shares offering one vote per share; and it has Class B shares — which are owned only by its founders, execs and key investors — that come with 20 votes per share.