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Market explainer
Market explainer

Why identical houses diverge in price The diffusion line effect explained

A look at how secondary lines blur price signals, with six concrete eBay examples that illustrate why a $2,300 blazer can list for $85.

17 Aug 20264 min

Many luxury houses run a second line built to a lower specification and sold at a lower wholesale tier. Resale platforms flatten that distinction, filing main-line and secondary-line pieces under one brand name, and most sellers do the same. The result is not random noise. It is a bias that runs in both directions, and it is legible if you know where the label boundary falls.

A main-line garment listed without its line marker inherits the price expectations of the cheaper label. A secondary-line garment listed under the parent name inherits expectations it cannot support. The first case is where the money is; the second is where buyers overpay while believing they have found the opposite.

What makes this tractable is that the evidence is usually printed on the tag. Akris Punto says Punto. Max Mara Weekend says Weekend. When a listing title omits the marker, that omission is itself information, and it is worth more than any judgement you can form from the photographs.

1
AKRIS Black and White Dotted Button Down Blazer Size 10
Akris
AKRIS Black and White Dotted Button Down Blazer Size 10
$85 vs $2,300 retail 96% below
Nothing in this listing title says Punto, which is the whole reason to look at it: the $2,300 retail figure belongs to the main line, and the $85 ask does not. A dotted pattern and a size 10 narrow the buyer pool well beyond what the brand name would suggest, which is the ordinary explanation for why it has not moved. Confirm the interior label before bidding, because the line distinction is carrying the entire case here.
2
Akris Punto Red Black Plaid striped Patterned blazer Business career size US 2
Akris
Akris Punto Red Black Plaid striped Patterned blazer Business career size US 2
$90 vs $1,095 retail 92% below
Punto is named in the title, so $1,095 is the correct reference and this is honest pricing rather than a mispricing. Size US 2 is the constraint worth noting: the smallest sizes turn over slowly on resale regardless of label, which compounds any discount already attached to a second line. The listing carries no condition description at all, so treat that as an open question and not as an absence of wear.
3
AKRIS PUNTO Wide Wale Charcoal Corduroy Trench Coat Size 8
Akris Punto
AKRIS PUNTO Wide Wale Charcoal Corduroy Trench Coat Size 8
$238 vs $1,895 retail 87% below
A corduroy trench shows how far the Punto label ranges while keeping the architectural cut Akris is known for. At $238 against $1,895 retail this is the narrowest gap in the group, which is what correctly labelled inventory usually looks like. Wide-wale corduroy crushes at the elbows and across the seat before it wears anywhere else, so request photographs of both areas.
4
Theory Belted Overlay Alpaca Wool Blend Coat Womens Medium Alps Plaid NO BELT
Theory
Theory Belted Overlay Alpaca Wool Blend Coat Womens Medium Alps Plaid NO BELT
$120 vs $695 retail 83% below
Theory operates no diffusion line, which makes it a useful control against the rest of this list. Here the discount from $695 retail to $120 has a stated cause printed in the title, and it is not a label question: the belt is missing. A belted overlay coat depends on that belt for its shape, so price a replacement into your bid or accept that you are buying a different garment than the one designed.
5
Max Mara Weekend Reversible Long Down Puffer Coat Tan & Mocha Brown Women's 10
Max Mara
Max Mara Weekend Reversible Long Down Puffer Coat Tan & Mocha Brown Women's 10
$120 vs $925 retail 87% below
Weekend is the casual label among the several Max Mara runs, and buyers who track only the flagship coats tend not to watch it. That inattention, rather than anything about this particular puffer, is what separates the $120 ask from $925 retail. Reversible construction doubles the surface that can stain or scuff, so look for images of both faces rather than the one the seller chose to photograph.
6
Max Mara Wool Coat Women's 10 Long Black Double Breasted Classic Moth Damage
Max Mara
Max Mara Wool Coat Women's 10 Long Black Double Breasted Classic Moth Damage
$125 vs $3,240 retail 96% below
Moth damage is stated in the title and left entirely unquantified, which is the reason this one is cheap and also the reason the numbers mean less than they appear to. A main-line double-breasted wool coat at $125 against $3,240 retail is the widest spread on this page, but that spread is theoretical until someone establishes whether the holes are two or twenty. Ask for close photographs of the shoulders, underarms and hem before you treat the figure as real.

Before you decide a listing is cheap, work out which line the garment belongs to and price it against that line's retail rather than the house's. Where the listing title carries no line marker at all, ask the seller for a photograph of the interior label; it is a one-message question that settles most of what follows.

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