Your Comps Are 6 Months Old: How to Time-Adjust Sold Prices So Your ARV Matches Today's Market

Why a Sold Comp Is a Snapshot, Not a Current Price

A sold comp tells you what one buyer paid on one day. If that closing happened seven months ago, the price reflects that month's interest rates, inventory, and buyer mood, not this week's. Appraisers handle this with a market conditions adjustment, usually called a time adjustment, that moves an old sale price to what it would likely bring today. Skip it, and your ARV rests on a market that no longer exists.

The error adds up quickly. Say a comp closed at $300,000 eight months ago and values in that pocket have slipped about 0.5% per month. That comp is worth roughly $288,000 today ($300,000 x 0.005 x 8 = $12,000 off). In a rising market the math runs the other way, and ignoring it makes you underbid and lose deals you should have won.

You do not need a published index to find the monthly trend. Three methods work with data you can pull yourself. Use more than one whenever you can.

1. Paired resales. Find the same house sold twice with no major renovation in between. Divide the price change by the months between sales for a clean monthly rate.
2. Median sold price per month. Track closings in a tight radius and narrow price band (for example, $250,000 to $350,000 within half a mile) over 6 to 12 months.
3. List-to-sale ratio drift. If homes that closed at 101% of list last spring now close at 96%, buyers have gained leverage, often before medians move.

No single method is perfect, so look for agreement. If paired resales and list-to-sale ratios both point down, trust the signal. If they conflict, apply a smaller adjustment and treat your ARV with more caution.

Order matters too. Time is the first adjustment, applied to the raw sale price before you touch square footage, condition, garage, or bedroom count. Adjusting features first applies the percentage to the wrong base and blurs which correction did what. Bring every comp to today's dollars, then compare the houses.

Worked Example: Softening Market, Three Comps, One Shrinking MAO

Say you're evaluating a 3-bed ranch that needs a full cosmetic rehab. You pull three solid comps within half a mile: one sold for $318,000 eight months ago, one for $305,000 five months ago, and one for $296,000 last month. The prices are already sliding, and when you check median sold price per square foot for the neighborhood, you measure a trend of roughly -0.6% per month.

To bring each comp to today's value, multiply the sold price by one minus the monthly trend times the months since sale. Eight months at -0.6% is a 4.8% drop, so the factor is 0.952. Here is the full math:

• Comp A: $318,000 x 0.952 = $302,736
• Comp B: $305,000 x 0.970 = $295,850
• Comp C: $296,000 x 0.994 = $294,224

The raw average of the three sold prices is $306,333. The time-adjusted average is $892,810 divided by 3, or about $297,600. That is an $8,700 gap in ARV, and almost all of it comes from the oldest comp. Comp A looked like your strongest evidence, but it was really a picture of a market that no longer exists. After adjustment, all three comps cluster within about $8,500 of each other, which tells you the adjustment is pulling them toward the same current reality.

Now run both numbers through the 70% rule with a $55,000 rehab. Using the raw average: ($306,333 x 0.70) - $55,000 = $159,433. Using the adjusted average: ($297,600 x 0.70) - $55,000 = $153,320. Your Maximum Allowable Offer drops by roughly $6,100 just by acknowledging the calendar.

That $6,100 doesn't disappear if you ignore it. It shows up later as a lower sale price, a longer days-on-market stretch, or a price cut while your holding costs keep running. In a softening market, an unadjusted ARV means you're agreeing today to absorb a loss you can already measure. Make the offer based on the $153,320 number, and if the seller won't meet it, you've lost a deal that was never really there.

Worked Example: Rising Market and the Temptation to Project Forward

Now flip the scenario. You're analyzing a 3-bed ranch, and your best comp is a similar house two streets over that sold 6 months ago for $250,000. Recent closed sales in the neighborhood show prices climbing about 0.4% per month. Over six months that's 2.4%, so the time-adjusted value is $250,000 x 1.024 = $256,000, which is what that comp would likely fetch today.

Here's the temptation. Your planned hold is 6 months and the market is rising, so why not add another 2.4% for the months ahead? That pushes ARV to $256,000 x 1.024 = $262,144. With a $40,000 rehab, your MAO jumps from ($256,000 x 0.70) - $40,000 = $139,200 to ($262,144 x 0.70) - $40,000 = $143,501, so you'd offer about $4,300 more for appreciation that hasn't happened yet.

The rule is simple: adjust comps forward to today's date, never to your projected sale date. The backward adjustment is measured from real closed sales, while the forward one is a forecast dressed up as data. If appreciation shows up during your hold, treat it as bonus profit. If you build it into your offer, you've paid the seller for your own optimism.

Then stress-test the exit by assuming the trend reverses at the same pace for your 6-month hold. A 0.4% monthly decline over six months takes your ARV to $256,000 x 0.976 = $249,856, roughly $6,100 lower. If you bought at $139,200, the 70% rule's margin absorbs that hit and you still profit. If you bought at $143,501 off the projected $262,144 ARV, you're now selling about $12,300 below the number your offer assumed, and that entire gap comes straight out of your profit.

Before you finalize an offer in a rising market, run this quick check:

• Is every comp adjusted to today, not to your sale date?
• Does the deal still pencil if ARV drops 2% to 3% during the hold?
• Would you still make this offer if prices went flat tomorrow?

Edge Cases: Seasonality, Thin Data, and Price-Band Splits

Not every price change between two closing dates is a market trend. Spring contracts close in late spring and summer, when buyer competition peaks, while winter closings often reflect fewer buyers and more motivated sellers. If one comp closed in May at $310,000 and a similar house closed in January at $298,000, that $12,000 gap (about 3.9%) looks like a falling market. Before you apply roughly 0.5% per month of downward adjustment, check the same months from the prior year. If prices dipped and then recovered on the same schedule, you are looking at seasonality, not a decline.

A market-wide trend can also hide what is happening in your slice of it. Metro medians might be up 2% year over year while homes in the $250,000 to $325,000 band sit longer and take price cuts. A single subdivision can move against the broader zip code too, especially when a new-construction phase floods it with competing inventory. Pull your trend from sales in the same price band, and ideally the same subdivision or school zone, rather than from a headline number.

Pending and active listings give you a forward check on stale sold data. Pendings are tomorrow's closings, so they show where contracts are being written now. Say your time-adjusted ARV is $320,000, but three nearby pendings listed between $305,000 and $312,000, and two actives have sat for 60+ days at $315,000. List prices are not sale prices, but they bracket reality, and here they tell you the adjustment is too generous.

Sometimes the honest move is to cap the adjustment or skip it. Treat your trend as untrustworthy if any of these apply:

• Fewer than five sales in your price band per quarter
• The trend disappears when you remove one outlier sale
• The implied change exceeds about 1% per month without a clear cause

In those cases, limit the total adjustment to a few percent, or leave it at zero and widen your profit margin instead. A thin sample produces an unreliable adjustment, and a wider margin protects you better than a precise-looking number built on noise.

Time-Adjustment Mistakes That Quietly Inflate ARV

Most time-adjustment errors are not dramatic. They are small, reasonable-looking choices that each add 1% or 2%, and together they turn a thin deal into a good one on paper. The first is using the list date instead of the close date. A home listed in March and closed in June sold to June's buyers, so adjusting from March adds three months of trend you never earned. In a market rising 0.5% per month, that is 1.5% on a $300,000 comp, or $4,500 of phantom value.

The second mistake is applying a metro or national trend to a single neighborhood. A metro median can climb 4% a year while one subdivision sits flat because of new construction nearby or a shift in school boundaries. Headline numbers also blend every price band, so starter homes and luxury homes get averaged together. Pull the trend from closed sales in the subject's own area and price range, even if the sample is small.

Third, investors adjust old comps upward in a cooling market out of optimism, assuming prices will bounce back by the time the flip lists. That is a forecast, not an adjustment, and it belongs nowhere in ARV. A related error is double-counting. If you already weighted your most recent comp at 60% because it best reflects today's market, then also time-adjust all three comps, you have priced the same trend in twice. Pick one method and apply it consistently.

Fifth, ignoring concessions makes recent sales look stronger than they were. A $310,000 sale with $9,000 in seller-paid closing costs is really a $301,000 net price. When concessions rise, gross sale prices can hold steady while net prices fall, which hides a softening market. Check MLS remarks and closing details on every comp before trusting the number.

FlipSmrt pulls recent MLS sold comps within 0.5 miles of the subject and adjusts them, which gives you a second ARV to test against your own time-adjusted figure. If the two land far apart, look at your close dates, trend source, and concession handling before you make an offer.

FAQ: Time Adjustments on Comps

How old is too old for a comp?

Sales from the last 90 days are ideal, and six months is a reasonable outer limit in most markets. Beyond that, the time adjustment does most of the work, which adds error to every number downstream. If you have to reach back 9 to 12 months, treat that comp as supporting evidence, not the anchor of your ARV.

Should I adjust per month or use a flat percentage?

Adjust per month, because a sale from 2 months ago and one from 6 months ago didn't close in the same market. At a 0.5% monthly decline, a $300,000 sale from 6 months back adjusts down 3% to $291,000, while a 2-month-old sale drops only 1% to $297,000. A flat percentage treats both the same and skews your ARV.

Do appraisers make the same adjustment?

Yes. Appraisers call it a market conditions adjustment and support it with local data, but their figures can lag a fast shift. Run the adjustment yourself so a low appraisal doesn't catch you off guard at the lender stage.

What if paired sales and median trends disagree?

Lean on paired sales (the same or a near-identical home selling twice), since they isolate time from changes in what sold. Medians can jump simply because more large or renovated homes closed that month. When the two conflict, use the more conservative figure.

Can I skip time adjustments in a flat market?

Only after you've confirmed the market is flat with current data. Compare list-to-sale ratios and days on market for the last 90 days against the prior 90. If both hold steady, a zero adjustment is a real conclusion, not a skipped step.

The practical rule: date-stamp every comp, adjust each one to today's market month by month, and only then set your MAO. On a $300,000 ARV, a 3% miss is $9,000, and at the 70% rule that's $6,300 of offer room you either gave away or never had.