Greater Boston homeowners who bought decades ago are sitting on some of the largest unrealized gains in the country. When those homes finally sell, often as part of downsizing, estate settlement, or a move out of state, the celebration at closing is followed months later by a harder conversation with the accountant: what exactly is your cost basis, and can you prove it?
For a straightforward case, basis is what you paid plus qualifying improvements, and the home sale exclusion of up to $250,000 for single filers or $500,000 for married couples filing jointly shelters much of the gain on a primary residence. But Greater Boston appreciation has pushed many long-held homes far past those exclusions, and several common histories make the basis question genuinely complicated.
The Situations That Need a Retrospective Value
Inherited years ago, never documented. If you inherited the home and no date-of-death appraisal was performed at the time, your stepped-up basis exists in principle but not on paper. The provision itself is worth understanding in full; the stepped-up basis tax benefit most heirs don't know they have until it's too late explains how the step-up works and why the missing documentation is what turns a benefit into a problem. A retrospective appraisal establishes the fair market value as of the date of death, even when that date is years in the past, using the sales data from that period. The methodology behind valuing a past date is the same discipline that governs estate work; how market conditions on the date of death affect taxable value explains why the appraiser reconstructs the market of that period rather than adjusting today's numbers backward.
Converted from a residence to a rental, or back. A conversion to rental use generally requires the property's fair market value at the conversion date for depreciation purposes, and unwinding the history at sale time without that number is painful. A retrospective appraisal reconstructs it.
Received through a divorce, a gift, or a family transfer. Each of these carries basis rules tied to values at specific past dates, and each is dramatically easier to resolve with a certified valuation anchored to the correct date.
Why Documentation Beats Recollection
When six figures of potential tax turn on a valuation, the IRS standard is not what the family remembers or what a website estimates a past year's value to have been. The same documentation standard applies when property moves between family members during life; gift tax and real property and why the IRS requires a qualified appraisal when you give a home covers the parallel rule for lifetime transfers. It is credible, documented evidence, and a USPAP-compliant retrospective appraisal, researched from the comparable sales of the relevant period, is exactly that. We note the general concepts here; the application to your return belongs with your CPA or tax advisor, working from documentation strong enough to rely on.
If a long-held Greater Boston property is heading toward sale this year, ask the basis question now, in July, while there is time to build the record properly. The closing will come and go quickly. The documentation is what remains when the tax return is filed.
To learn how Aladdin Appraisal serves homeowners, attorneys, realtors, CPAs, and investors across Greater Boston, visit our full appraisal services page.
