Working out what to charge

The only property in this estate where cost-plus does not apply at all.

Not a cost-plus calculation

Two specimens with identical acquisition costs can differ in value by a hundredfold. What you paid tells you what you must beat, not what it is worth.

So this is a comparison exercise, and the tool is a method rather than a formula.

The comparison method

Find three comparables: same species, same locality, similar size class and quality.

Use realized prices rather than asking prices. Completed auction results, what actually sold at a show, what a dealer told you they got.

Then adjust from the nearest comparable rather than averaging all three, and write down which one you used so next time is consistent.

Adjusting from a comparable

Upward: better form, better lustre, undamaged where the comparable was chipped, better matrix, documented provenance, a locality now closed.

Downward: damage, and discount it properly. A repaired or chipped specimen is worth materially less and sellers routinely under-discount it.

Downward: no locality data, which is a large discount and not a small one.

Downward: a treatment, disclosed.

Neutral: what you paid, and what the trip cost.

Your own costs

Not in the price of the individual specimen, but they are real and they belong in the year's arithmetic.

Acquisition, processing time, boxes and housing, show fees and travel, shipping, and the storage environment.

Work them out annually against total sales rather than trying to allocate them per specimen, which is the calculation that actually tells you whether the dealing is a business.

References