- $500 million worth of "convertible senior notes" due 2025, and
- $500 million worth of Class C common stock (that's the one that trades under ticker symbol "Z").
At Zillow's current stock price of just about $52 per share, the company will issue about 9.6 million new Zillow C-shares. In an accompanying press release, Zillow announced that it "intends to use the net proceeds from the Shares Offering and the Notes Offering to repurchase a portion of its outstanding 2.00% convertible senior notes due 2021" (thus rolling over old debt), but also, potentially, for "acquisitions of, or investments in, other businesses, products or technologies" (i.e. to grow the business).