On November 2, 2021, Zillow announced its third quarter results. While total revenues were up 88% in comparison to 2020, Zillow missed its guidance and announced that they were shutting down their largest revenue stream, Zillow Offers.. The news wiped off 45% of Zillow’s market cap in less than a week. Zillow also announced layoffs of up to 25% of their staff. The root cause has been laid at the feet of Zillow’s AI Zillow’s algorithms overestimated the value of the homes for which they paid. At the same time, Zillow was aggressively expanding its purchasing program, acquiring more homes in the last two quarters than it had in the two years prior. Zillow’s Offer algorithm leveraged Facebook’s Prophet Python AI library.