What Is Home Price Index (HPI)?
A home price index tracks changes in residential property values over time using a consistent methodology that controls for housing mix differences. The three major U.S. indexes — S&P CoreLogic Case-Shiller, FHFA HPI, and Freddie Mac HPI — all use repeat-sale methodology, measuring how the same properties appreciate or depreciate across transactions.
Key Facts
- The S&P CoreLogic Case-Shiller National Home Price Index rose approximately 47% from January 2020 to late 2025, representing the fastest sustained appreciation since the index began in 1987
- Home price indexes use repeat-sale methodology — tracking the same properties across multiple sales — which eliminates the mix bias that distorts median price comparisons when the type of homes selling changes
- The FHFA HPI covers only conforming, conventional mortgages purchased by Fannie Mae and Freddie Mac, while Case-Shiller includes all transactions including cash sales and jumbo loans
- During the 2008 crisis, the Case-Shiller National Index fell 27% from peak to trough (2006-2012) — the index's ability to capture this decline validated its methodology for tracking housing distress
- The ADI does not directly incorporate home price indexes into its composite score, but monitors them as context indicators because price declines are the mechanism that converts stretched affordability into actual defaults
Live Data
How Home Price Indexes Work
Home price indexes differ fundamentally from median home price statistics. The median tells you the midpoint sale price in a given period — but if more expensive homes happen to sell this month, the median rises even if individual home values haven't changed. This is called mix bias.
Home price indexes solve this by using repeat-sale methodology: they track the same properties across multiple sales. If a home sold for $300,000 in 2020 and $400,000 in 2024, that pair contributes a 33% appreciation data point. By aggregating thousands of such pairs, the index isolates actual price appreciation from mix changes.
Major U.S. Home Price Indexes
- S&P CoreLogic Case-Shiller: The most widely cited index. Covers 20 metro areas plus a national composite. Includes all transaction types (conventional, FHA, VA, cash, jumbo). Published monthly with a 2-month lag. The 20-city composite is the benchmark for housing market commentary.
- FHFA House Price Index: Published by the Federal Housing Finance Agency. Covers only conforming, conventional mortgages backed by Fannie Mae and Freddie Mac. Broader geographic coverage than Case-Shiller (all 50 states, 400+ metros) but narrower transaction scope.
- Freddie Mac House Price Index: Monthly index using Freddie Mac's loan database. Covers the same conforming market as FHFA but with different weighting. The American Distress Index references this among its context indicators.
Why Home Price Indexes Matter for Distress
Home prices are the hinge between affordability stress and actual default. When prices are rising, even a homeowner struggling with payments has options — sell the home, cash out equity, or refinance. When prices fall, those options disappear. A homeowner who owes more than their home is worth (negative equity) cannot sell without bringing cash to closing, cannot refinance without equity, and faces foreclosure as the only exit if they can't make payments.
This is why the ADI's GFC backtest is so informative: the Case-Shiller peak in 2006 preceded the foreclosure peak by roughly two years, with the price decline converting pre-existing affordability stress into mass default. The ADI captures the same dynamic through its Buffer Depletion leading indicator thesis.
Frequently Asked Questions
What is the best home price index?
Case-Shiller is the most widely cited and covers all transaction types. FHFA offers broader geographic coverage (400+ metros vs. Case-Shiller's 20). For local market analysis, Zillow's Home Value Index provides the most granular zip-code level data. No single index is best — they measure slightly different things.
How does a home price index differ from median home price?
The median is the midpoint sale price in a given period — it changes when the mix of homes selling changes. A home price index uses repeat-sale methodology to track the same properties across transactions, isolating actual appreciation from mix bias.
How often are home price indexes updated?
Case-Shiller publishes monthly with a 2-month lag (January data releases in late March). FHFA publishes quarterly for the purchase-only index and monthly for the all-transactions index. Zillow publishes monthly with about a 1-month lag.
Are home prices still going up?
As of late 2025, national home price indexes show modest year-over-year appreciation in the low single digits, well below the double-digit gains of 2021-2022. Some metros show flat or slightly declining prices. The pace depends heavily on local supply conditions.
How do home price indexes connect to the American Distress Index?
The ADI monitors home prices as context rather than a direct composite input. Price declines are the mechanism that converts affordability stress into actual defaults — when falling prices eliminate equity, homeowners lose their exit options. The GFC backtest demonstrates this: Case-Shiller peaks preceded the ADI entering Crisis zone by roughly two years.