How third-party grading works, when slabbing adds value, and when it just adds plastic.
Third-party coin grading is the process by which an independent service inspects a coin, assigns a numerical condition score, and seals it in a tamper-evident plastic capsule — a 'slab' — with the grade printed on the holder. The two dominant services are PCGS and NGC, both based in the United States, both with established secondary-market recognition.
Grading adds genuine value to high-end numismatic coins where small differences in condition translate to large differences in price. A 1928 Sovereign in MS-65 might trade at three times the price of the same coin in MS-62. For modern bullion, however, the maths rarely works. The grading fee, return shipping, and insurance often consume any premium the slab earns.
“Grading adds genuine value to high-end numismatic coins where small differences in condition translate to large differences in price.”
Our rule of thumb: if the coin's premium over spot exceeds twenty per cent and the issue date is pre-1950, grading is worth considering. Anything more modern or more bullion-grade and the plastic is just plastic.
We can arrange submission to either service on behalf of clients and routinely do so for inherited collections being prepared for sale.
