Like much of the industry, Zillow's mortgage operation, which includes Zillow Home Loans, has seen a steep decline in revenue and continues to burn cash.

Why it matters: Attaching mortgage is a key component of Zillow's "Housing Super App" and future growth strategy; the longer it falters, the less likely Zillow is to achieve its long-term aspirations.

• Zillow's 2025 goal includes an additional $800 million in revenue from adjacent services -- primarily mortgage.

Dig deeper: Zillow's mortgage segment, which includes its mortgage lead gen marketplace and in-house lender Zillow Home Loans, is consistently unprofitable.

• In the first half of 2022, Zillow spent $1.85 for every $1 in mortgage revenue.
  
  

• That's a $65 million loss in the first half of 2022, and a combined loss of $180 million since 2017.

Context: The entire mortgage industry is getting hammered this year, with dropping leads, loan volumes, and revenue.

• But even before the recent slowdown, Zillow Home Loans struggled with attach rates and consistent unprofitability during boom years.
  
  

• According to this Mortgage Bankers Association study, 96 percent of mortgage firms were profitable in 2021; Zillow Home Loans was not.

The bottom line: Zillow Home Loans' path to profitability remains long, arduous, expensive, and uncertain.

• Ultimately, attaching mortgage makes a great slide on investor presentations, but is very hard in real life.
  
  

• Go deeper: Ecosystem Disruption in Mortgage Looking Exceedingly Traditional.