For Boston, MA, the five-digit label 02128 is both the Zillow ZIP market identifier and the matched Census ZCTA; a ZCTA is a statistical area and is not identical to a USPS delivery ZIP. For June 2026, its current Zillow ZORI is $3,199 per month, up 3.5% year over year. ZORI is a typical observed asking-rent index blended across rental types rather than a record of signed leases or a bedroom-specific survey. The cross-source tension appears in the direct ZIP Redfin median sold price of $679,846, which increased 0.72% year over year. Annualized ZORI divided by that price is a 5.65% cross-source screening ratio. It is not a cap rate, net return, expected return, or property yield, and the two measures describe distinct markets.
The backward-looking Zillow history at the stated endpoint gives a rising but slowing sequence: exact same-month annualized change was 3.5% over one year, 4.2% over three years, and 5.9% over five years. The latest positive move therefore confirms rather than breaks from the longer upward path, but its rate is lower than both longer-window rates. Coverage reaches 99.2%, broad enough to support the historical measurement. Annualized variability in monthly rent returns is 3.2%, making a single current rent snapshot less certain than a steadier sequence might allow. Separately, the maximum drawdown was -8.5%, evidence of a past peak-to-trough reversal in the series. Transparent national discovery ranks were 647 for momentum, 1,912 for stability, and 990 for balanced among history-eligible ZIPs; lower ranks are higher. These backward-looking ranks and measurements are not forecasts or investment recommendations.
The local FY2026 HUD ladder is used only to scale the ZIP ZORI into modelled monthly estimates: $2,258 for a studio, $2,438 for one bedroom, $3,199 for two, $3,999 for three, and $4,236 for four. These are modelled estimates, never measured bedroom rents; the two-bedroom figure coincides with ZORI because the ladder sets that reference point. HUD FMR/SAFMR is an administrative, bedroom-specific standard rather than asking rent. For scale, the local HUD two-bedroom standard is $2,311, leaving the modelled two-bedroom estimate 38.4% above it. That gap does not establish a landlord's asking price, an eligibility result, or the price of an individual unit.
Affordability must not blend the survey into the asking index. In the matched ZCTA, ACS 2024 five-year median gross rent was $2,064. ACS median gross rent is a five-year survey of occupied renter homes and includes selected utilities, unlike ZORI's blended typical asking-rent index. The current ZORI stands 55.0% above that survey median. The ZCTA median household income was $90,106; applying a 30% screen to annualized ZORI produces $127,960 required income, while annualized ZORI equals 42.6% of that median income. The required-income screen is arithmetic, not advice or an applicant qualification rule. ACS also estimates that 47.0% of renter households were burdened at or above that threshold; this does not prove the burden of a particular unit.
Tenure and vacancy provide a composition screen rather than a list of vacancies. The ACS ZCTA counts 19,193 housing units, a 7.6% vacancy rate, and a 71.0% renter share. Within the recorded vacant-unit categories, 259 units were vacant for rent; the total also contains other vacancy statuses. The structure table records 3,763 units in large multifamily buildings, more than in its single-family category. These counts do not indicate which units are currently offered, their condition, asking terms, or accessibility. Nor does the vacancy rate establish availability at a particular property. They are stock and survey classifications, which need to remain separate from Zillow asking rents and Redfin resale transactions.
Broader figures sharpen the location comparison without replacing ZIP evidence. The City of Boston context rent is about $3,469, the Suffolk County context rent is $3,423, and the Boston–Cambridge–Newton, MA–NH metro context rent is $3,210; each has its named wider scope. ZIP ZORI is below the city and county context values and close to the metro context value. The ZIP's renter share is higher and its vacancy rate lower than the City of Boston and Suffolk County context measures, but such contrasts cannot describe an individual building or a sub-ZIP area. City, county, and metro figures are context only, not rental comparables, substitute ZIP observations, or evidence of causation.
Redfin's direct rolling-three-month ZIP resale observation provides liquidity signals only for the for-sale market. It reports 98 homes sold, a median 24 days on market, an inventory of 152 homes, and 4.7 months of supply. Its sale-to-list average was 99.08%, while 25.29% of sales closed above list. These are resale closing and marketing observations, not rental transactions, property operating results, or a forecast. Alongside the much slower resale-price change stated above, the liquidity block challenges a simple assumption that the asking-rent increase is mirrored by resale appreciation. It does not resolve whether any particular property can command the index rent, trade near the ZIP median, or sell on those timing terms.
The screens have material limits. Zillow measures a blended ZIP asking-rent index; ACS is a multiyear survey with margins of error and selected-utility treatment; HUD supplies an administrative standard; and Redfin observes ZIP resales over a rolling window. A property-level review would need the live advertised rent, exact bedroom count, included utilities, lease length, concessions, availability date, and the appropriate HUD standard if relevant. It would also need a property's own sale history, current listing status, and sale-to-list evidence rather than the ZIP median. Those checks can test fit to the screens but cannot turn backward-looking trends into a forecast. Do current unit-level terms and property-specific resale records line up with the separate area measures?
","findings":[{"body":"The current 3.5% increase confirms upward rent movement, but trails the annualized same-month rates for the three-year and five-year windows. Near-complete history coverage supports the measurement, yet monthly variability and the recorded drawdown argue against treating one index point as definitive. National ranks are transparent relative discovery markers, not forecasts or investment signals.","title":"A slower current step follows a stronger historical path"},{"body":"Zillow ZORI and ACS gross rent do not measure the same rent universe. ACS summarizes occupied renter homes over five years and includes selected utilities, whereas ZORI is a current blended asking-rent index. Their gap is therefore a source-scope difference, not evidence that either source is wrong. Income and burden figures provide arithmetic and survey context, but neither qualifies an applicant nor proves unit-level burden.","title":"Asking rent, survey rent, and income are separate screens"},{"body":"HUD supplies a bedroom-specific administrative standard, and scaling ZORI by its local ladder produces internally consistent modelled monthly estimates. They do not measure advertised or signed rents by bedroom. Redfin measures ZIP resale activity separately; its price denominator creates a high-level screening ratio only. The ratio does not describe property finances, an expected outcome, or a rental transaction.","title":"Bedroom modeling and resale pricing remain distinct"},{"body":"ACS stock data show a renter-majority occupancy profile, recorded vacant-unit categories, and a large-multifamily count exceeding the single-family count. This frames the ZCTA's surveyed housing composition but does not reveal a currently rentable address. Live advertisements, unit bedroom count, utility inclusions, lease terms, and date-specific availability remain separate checks for any property-level comparison.","title":"Survey stock frames composition, not immediate availability"}],"risks":["ZORI aggregates observed asking rents across rental types, so it cannot establish the asking rent, concessions, utility terms, condition, or availability of any specific apartment.","ACS estimates describe a multiyear matched ZCTA survey and carry sampling uncertainty, while current asking-rent and resale series use different timing and universes; direct comparisons can overstate precision.","The HUD-scaled bedroom figures are modelled from an administrative ladder rather than observed unit rents, so atypical layout, utility inclusion, lease terms, and concessions remain unobserved.","The Redfin window is ZIP-level resale evidence; a median price, sale-to-list statistic, or marketing-time figure cannot document an individual building's sale outcome, condition, or rental economics."],"qa":[{"a":"They are intentionally different evidence universes. The ACS matched ZCTA estimate summarizes occupied renter homes over five years and incorporates selected utilities, whereas Zillow ZORI is a current typical observed asking-rent index blended across rental types. Timing, utility treatment, and occupancy status differ, so the figures are not interchangeable.","q":"Why is the ACS gross-rent figure lower than the current Zillow ZORI?"},{"a":"No. HUD supplies a bedroom-specific administrative FMR/SAFMR standard, and the report scales the single ZIP ZORI by its local HUD ladder to create consistent studio through four-bedroom modelled monthly estimates. The two-bedroom point is the index reference. These calculations are not measurements of advertised, leased, or currently available bedroom-specific units.","q":"Are the bedroom estimates observed rents for available apartments?"},{"a":"No. The ratio divides annualized Zillow ZORI by the Redfin ZIP median sold price, so it is only a cross-source screening calculation. Zillow supplies an asking-rent index, while Redfin supplies a rolling ZIP resale observation. The ratio is not a cap rate, property yield, net return, expected return, or statement about a particular property.","q":"Does annualized ZORI divided by median sold price establish a property return?"},{"a":"The history is backward-looking, not predictive. Positive same-month changes at the one-year, three-year, and five-year horizons show that the current direction remains upward relative to earlier reference months. However, variability measures month-to-month dispersion and maximum drawdown records a past peak-to-trough decline. Together they support treating current ZORI as a useful index reading with uncertainty, rather than as a guaranteed trajectory.","q":"How do historical variability and drawdown change confidence in current ZORI?"}],"sources":[{"key":"apartment_list_time_on_market","name":"Apartment List Time on Market — listing liquidity","release":"Apartment List 2026-07","pulledAt":"2026-08-08","url":"https://www.apartmentlist.com/research/category/data-rent-estimates"},{"key":"apartment_list_vacancy","name":"Apartment List Vacancy Index — rental vacancy","release":"Apartment List 2026-07","pulledAt":"2026-08-08","url":"https://www.apartmentlist.com/research/apartment-list-vacancy-index-methodology"},{"key":"census_zcta_facts","name":"Census ACS five-year — ZCTA housing and income","release":"ACS 2024 5-year ZCTA","pulledAt":"2026-08-08","url":"https://api.census.gov/data/2024/acs/acs5.html"},{"key":"hud_zip","name":"HUD USPS crosswalk and Small Area FMRs — ZIP rent fallback","release":"ZIP-CBSA 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