The measured IRS flow was 15,641 tax-return households moving from San Jose to San Francisco, associated with 24,523 exemptions and $207,287.39 of AGI per return. IRS flow means tax-return households; it does not identify renters, every mover or future demand. The evidence therefore establishes a financially substantial filer corridor, not a count of renter relocations or a forecast of leasing demand. It is the starting signal, not the demand model.
For a household shopping at the metro asking-rent snapshot, San Francisco was $3,301 per month, compared with $3,729 in San Jose. The annual destination change was -$5,136. Buying presents a larger market-level reset: the destination’s home-value gap was -$441,641. Directionally, the move lowers the headline entry price and asking rent, but those metro measures do not match neighborhood, unit size, commute, lease concession or ownership carrying costs. Actual savings can differ materially by submarket and tenure.
For underwriting, lower price is not the same as lower household burden. The destination’s market-level gross yield was 3.47% versus 2.83% in San Jose, but its median household income was $26,084 lower and its rent-to-income measure was 29.12%. The next underwriting question is whether a specific San Francisco asset’s achievable rent, vacancy, taxes, insurance, association charges, maintenance and financing still produce acceptable cash flow after unit-level condition and tenant profile are verified. That is the decision the market averages cannot answer, and neither market is a universal winner on these aggregates.

