Kiton was founded by Ciro Paone and built its reputation on Neapolitan hand tailoring at a scale almost no other house attempts. The name is shorthand for the top of the Italian ready-to-wear market, and the retail prices reflect labour rather than marketing.
The house works in tiers. Its standard jackets already carry more handwork than most of what sits beside them in a good shop, and its top commissions involve considerably more again, along with fabrics reserved for that level. Vicuña and cashmere appear regularly enough that the material alone can account for a large share of a given jacket's retail price.
That tiering is the thing to understand before looking at any listing. Two jackets with the same name on the label can represent very different amounts of work.
Kiton discounts steeply secondhand, which is unremarkable; almost everything does. What is unusual is how far the discount runs, because buyers anchor to a retail number they have read about rather than to what the garment is worth as a used jacket. The result is a floor set by sticker shock rather than by construction.
The second distortion is the sub-labels. KB is Kiton's lower line, and sellers routinely list it simply as Kiton, or as K50, either because they do not know the difference or because the distinction does not help them. Listings therefore price by brand name and not by tier.
That cuts both ways. It is where a patient buyer finds a genuinely hand-tailored jacket at contemporary-blazer money, and it is also how a careless one pays K50 prices for KB.