Portal Stocks Make Fresh Lows: Zillow RSI 21, CoStar RSI 17 — Both Below $28 as the Transaction Drought Deepens

Portal Stocks Make Fresh Lows: Zillow RSI 21, CoStar RSI 17 — Both Below $28 as the Transaction Drought Deepens

Both tracked portal/data names broke below their September lows in the first week of October as mortgage rates ran to 7.28% (see Mortgage Rates Hit 7.28% — Sixth Straight Weekly Increase — as the Jobs Report Collapses to +29K):

• Zillow Group (Z): $27.41, -22.4% in one month, -64.9% from its 52-week high, RSI 21 (deeply oversold), 35.9% below its 200-day moving average — a fresh low beneath the $29.13 trough hit in September. Market cap $6.16B.
• CoStar Group (CSGP): $27.38, -13.6% in one month, -67.7% from its 52-week high, RSI 17, -58% year to date, pressure compounded by its removal from the FTSE All-World Index. Market cap $11.09B.

The striking fact is the divergence between price and fundamentals. Zillow's TTM revenue is up 17.9% ($2.81B) with EPS beats in three of four quarters; CoStar's TTM revenue is up 18.4% ($3.56B) with EPS beats in all four, and Q2 operating income swung to $76.0M from -$51.1M a year earlier. The market is not pricing portal earnings — it is pricing transaction volumes, which are freezing (existing-home sales 3.98M SAAR, pending sales at index 71.2).

A new signal from CoStar's own data: the Apartments.com September 2026 rent report shows the national average rent fell 0.08% to $1,752 — the first decline after nine months of positive-or-flat growth. Rental softness matters for the for-sale market because it removes the "relist as a rental" exit that has kept would-be resale sellers off the market¹ (the Zillow analysis in New Homes Now Cheaper Per Square Foot Than Existing in a Third of Major Markets — Zillow Quantifies the Builder-Discount Economy flags this option explicitly).

CoStar reports Q3 2026 results on October 27 — the same day as the September new-home-sales release, making it a same-day read on both portal fundamentals and builder volumes.