The relative-price spread between a NEW home and an EXISTING home determines builder competitiveness. Historically new homes carry a ~10-25% premium over existing (better quality, location, amenities). When that premium compresses or inverts, builders win share — their biggest single share-gain windows in the past 30 years all happened when the gap closed. Currently watching the spread + the 12mo trend.
Both quarterly. Existing-home median is from NAR-licensed series; new-home median is from Census Bureau directly.
Computed as (new − existing) / existing. Historical norm is +10-25%; below +10%
= builders are share-gaining; below 0% = builders pricing aggressively to clear inventory
(rare, see 2009).