In ZIP 02139, the supplied June 2026 data expose a cross-market tension rather than a single direction. Zillow ZORI, the ZIP-level asking-rent measure, stood at $3,818 per month and was 4.31% higher than a year earlier. In contrast, Redfin's direct rolling-three-month ZIP resale observation through the supplied June endpoint put the median sold price at $1,129,745, a 19.59% year-over-year decrease. Zillow is a typical observed asking-rent index blended across rental types; Redfin records completed for-sale transactions, not rental transactions. Thus the decline in the resale median challenges any uncomplicated reading of the rent increase, without converting either series into a claim about the other market.
History shows a continuing but uneven rent path. Exact same-month annualized ZIP ZORI changes were 4.31% over one year, 3.89% over three years, and 5.63% over five years. Recent direction therefore confirms the longer upward path, although it is slower than the five-year pace and only modestly stronger than the three-year pace. Its annualized monthly-return variability is 3.22%; that amount of movement means a current snapshot should not be treated as a perfectly smooth signal, even with strong history coverage. The historical maximum drawdown reaches 11.94%, independently showing a material past retreat. The series has complete coverage. Its transparent national discovery ranks are 589 for momentum, 1,930 for stability, and 915 for balanced history; lower ranks place higher. These are backward-looking measurements, not forecasts or investment recommendations.
This five-digit label functions both as the Zillow ZIP market identifier and as a Census ZCTA match. A ZCTA is a statistical area, not the same thing as a USPS delivery ZIP. The matched ACS 2024 five-year survey reports a $2,691 median gross rent among occupied renter homes, including selected utilities; the current asking index is 41.9% above it. That gap is a source-universe difference, not an inconsistency: ACS surveys occupied renter homes, while ZORI tracks typical observed asking rent. For wider, explicitly contextual comparison, the City of Cambridge context rent is $3,598, the Middlesex County context rent is $3,260, and the Boston-Cambridge-Newton, MA-NH metro context rent is $3,210. None of those city, county, or metro values substitutes for the ZIP measure.
The bedroom profile is a scaled screen, not a set of observed ZIP rents. Modelled estimates derived by scaling ZIP ZORI with the local HUD ladder are $2,695 for a studio, $2,909 for one bedroom, $3,818 for two bedrooms, $4,773 for three bedrooms, and $5,055 for four bedrooms. The FY2026 local HUD ladder is the scaling input. HUD FMR/SAFMR is an administrative, bedroom-specific standard rather than an asking-rent observation, so neither its benchmark nor the modelled estimates should be read as measured asking rents for a particular layout. The equality of the modelled two-bedroom figure and the headline ZORI reflects the scaling method, not a direct two-bedroom rent survey.
Income and burden data point to a different tension. In the ACS survey, median household income is $134,586. Applying the arithmetic 30% screen to the monthly ZORI produces a required annual income of $152,720, while the asking-rent-to-median-income calculation is 34.0%. This screen is arithmetic only, not advice and not an applicant qualification rule; ZIP-wide median income also does not identify a renter household's resources. Among 10,862 ACS renter households, 4,614, or 42.5%, reported gross-rent burdens at or above that threshold. Because ACS is a five-year survey of occupied renter homes and uses selected utilities in gross rent, this burden measure cannot establish the affordability, utility bill, or lease terms of any particular unit.
Housing stock provides denominators but not listing-level availability. The ZCTA survey estimates 17,034 housing units, including 16,012 occupied and 1,022 vacant units, for a 6.0% vacancy rate. Of the vacancies, ACS separately categorizes for-rent and seasonal units; those categories are survey classifications rather than live advertised inventory. They do not demonstrate that a specific apartment is available, explain its rent, or prove a vacancy condition for a particular property. The renter-household lens applies to most occupied homes in this geography, while the vacancy reading must remain separate from current Zillow asking-rent observations and Redfin for-sale listings.
Redfin's ZIP resale evidence gives the price decline needed context without becoming rental evidence. Its rolling-three-month observation records 70 homes sold, a median 22 days on market, and inventory of 52 homes. Months of supply were 2.2, a stock-to-sales measure that translates reported inventory into months at the current sales pace, not a projection of future availability. The average sale-to-list ratio was 103.97%, and 52.99% of sales closed above list. Alongside the falling median sold price, these direct resale liquidity signals are mixed: sales were occurring with those list-relative outcomes even as the median fell. That price decline challenges a simple inference from rising asking rents, their longer history, or the ZIP-wide income screen to resale pricing.
The annualized ZIP ZORI divided by the ZIP median sold price is 4.06%, a cross-source screening ratio only. It matches neither a property's rent roll nor its expenses, debt terms, taxes, insurance, maintenance, vacancy experience, or transaction costs, and it cannot establish future performance. ZORI's rental-type blend, ACS sampling and stated margins of error, HUD's administrative design, and a rolling resale window all limit one-number conclusions. Property-level checking would need the current advertised rent and availability, bedroom and layout, included utilities, lease timing and concessions, unit condition, and comparable completed sales rather than the ZIP median alone. The decision tension remains explicit: does the particular property's documented rent and cost information support the broad rent signal despite the resale median's decline?
","findings":[{"body":"ZIP ZORI was $3,818 in June 2026, up 4.31% year over year. The exact three- and five-year annualized changes of 3.89% and 5.63% show that the latest rise continues a longer upward history but is below the five-year pace. Complete historical coverage supports measurement continuity, while the recorded drawdown means that continuity does not imply a smooth path.","title":"Rent path remains upward but not smooth"},{"body":"ACS describes occupied renter homes rather than current listings. Its median gross rent of $2,691 includes selected utilities, whereas ZORI is an asking-rent index. Applying 30% of income to the ZIP asking index yields $152,720 in required annual income, an arithmetic benchmark only. The burden share measures reported household conditions across the ZCTA survey, not eligibility or a particular apartment's affordability.","title":"Budget screen differs from observed renter conditions"},{"body":"HUD's bedroom-specific administrative ladder is used only to scale the ZIP-wide asking index into modelled studio through four-bedroom estimates. It does not measure observed asking rents by bedroom. The ZCTA housing counts and vacancy categories are similarly survey-based context: they identify stock and occupancy patterns, but cannot confirm whether a given unit is vacant, marketed, or leased at the index value.","title":"Bedroom and vacancy figures are not listing evidence"},{"body":"Redfin's direct rolling-three-month ZIP resale data show the median sold price falling while 70 homes sold, the median marketing period was 22 days, supply was 2.2 months, and the average sale-to-list ratio was above list. Those are for-sale transaction signals, not rental comparables. The 4.06% annualized-rent-to-price result is only a cross-source screen and cannot establish property-level economics or future outcomes.","title":"Resale signals conflict with a simple rent-to-price reading"}],"risks":["ZIP ZORI blends rental types and is a typical asking-rent index, so it cannot establish the actual rent, concessions, timing, or utility treatment for a specific apartment.","The ACS ZCTA series is a five-year survey with sampling uncertainty and selected-utility treatment. It may not match present listing rents, current household income, or lease costs at a specific address.","The resale median, days on market, inventory, and sale-to-list values all refer to for-sale activity over a rolling window. They cannot be used as rental transactions, building-level comparable rents, or proof of sale terms for a unit.","Modelled bedroom estimates inherit the ZIP-wide ZORI and HUD ladder rather than direct bedroom observations. A property's layout, condition, utility inclusions, concession structure, and lease timing can differ materially from that screen."],"qa":[{"a":"The label is used two ways in the supplied packet: Zillow's ZIP market identifier and the matched Census ZCTA. A ZCTA is a statistical area assembled for census reporting, not an identical representation of a USPS delivery ZIP. Consequently, the ACS evidence is area-level survey context rather than a delivery-route or property boundary.","q":"What geography does 02139 represent in this report?"},{"a":"The measures cover different universes. ZORI summarizes typical observed asking rent across rental types at ZIP level. ACS median gross rent comes from a five-year survey of occupied renter homes and includes selected utilities. The gap can reflect the measures' distinct timing, occupancy, and utility treatments, so it does not by itself demonstrate an error in either source.","q":"Why is ACS gross rent below Zillow ZORI?"},{"a":"The stated required annual income simply divides the ZIP asking-rent index by the 30% share. It is an arithmetic screen, not advice, an underwriting decision, or an applicant qualification rule. ACS burden is a survey estimate across occupied renter households; it cannot determine one household's budget, utility payment, lease offer, or outcome at a specific address.","q":"How should the income and burden figures be used?"},{"a":"No. Redfin's direct rolling-three-month figures describe completed ZIP resale transactions and listing-market conditions, whereas ZORI covers asking rents. A falling resale median and above-list indicators can coexist in this packet, producing a cross-market tension. The annualized-rent-to-price computation is only a screening ratio and cannot determine expenses, financing, individual property economics, or future prices.","q":"Does Redfin validate rent levels or predict future prices?"}],"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 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