KEY POINTS
  • Amazon disclosed advertising for the first time on Thursday.
  • Amazon said its advertising business is growing 32%, and booked $31 billion last year.
  • The company hasn't said how profitable the unit is.

Amazon revealed Thursday just how big its advertising business has become. It generated $31.2 billion in revenue in 2021, with fourth-quarter sales rising 32%, according to the retailer's fourth-quarter earnings statement.

The disclosure follows years of Amazon investing in the advertising business and keeping details private.