This article examines index revision in measuring the prices for owner-occupied housing. We consider revision in the context of equity insurance and the settlement of futures contracts. The usefulness of aggregate housing price indexes in these contexts requires stability as they are extended. Methods that are subject to substantial revision raise questions about the viability of derivatives markets. We find that the most widely used house price indexes are not equally exposed to volatility in revision. Hedonic indexes appear to be substantially more stable than repeat-sales indexes and are not prone to the systematic downward revision found in the repeat-sales indexes.