PF vs MS vs AU: Understanding Coin Grades and Why They Matter for Investors

If you are new to graded coin investment, the first thing you will see on a slab is a string of letters and numbers, PF70, MS69, AU58. The grade tells you what the coin is, how it was made, and roughly where it sits in the market. It is worth understanding before committing capital.

Proof (PF) coins go through a specialised minting process. The blanks (planchets) are polished to a mirror finish before striking. The dies are treated and polished to give razor-sharp detail. Each coin is struck more than once at lower press speeds, producing the frosted devices and deeply reflective fields that make a proof instantly recognisable.

PF grades run from PF1 to PF70 on the Sheldon scale, but for investment purposes the relevant range is PF68 to PF70. A PF70 coin is considered perfect, no marks, no flaws, nothing under 5× magnification. Grading at this level is exacting, and only a small fraction of any proof mintage gets there. That is precisely why the premiums are what they are.

Mint State (MS) coins are produced for general circulation, or at least using the standard production process. They are struck once at full press speed from unpolished dies and planchets. They are not meant to look like proofs; they have the lustre that collectors call ‘cartwheel’ brilliance when tilted under light.

MS also runs from 1 to 70. An MS70 is flawless, but the surfaces are bright and lustrous rather than mirrored. MS67 and above is generally treated as gem quality and is the tier most relevant to investors. Below MS65 you start to see contact marks from production handling.

About Uncirculated (AU) sits just below Mint State, covering AU50 to AU58. These coins have not really been used in commerce, but they show slight wear on the highest points of the design. The visual gap between AU58 and MS60 is small. The price gap is not.

For investors in modern graded coins, AU is generally not investment grade. Historic coins are a different matter, an AU example of an 18th-century issue can be extremely valuable on the basis of age and rarity alone. Modern AU usually just means the coin was not handled well.

Why does the PF vs MS distinction matter? Scarcity and demand. Proof coins are produced in much smaller numbers than their MS equivalents. The Royal Mint might strike 10,000 proof Sovereigns versus several million bullion Sovereigns in the same year. Of those 10,000 proofs, perhaps 500 to 1,000 will grade PF70. That built-in scarcity is what creates the premium.

Premiums above gold content show the effect clearly. A bullion Sovereign trades at roughly 5 to 10 percent above its melt value. A PF69 proof Sovereign from a collectible year might trade at 50 to 100 percent above melt. A PF70 example of the same coin can sit at 200 to 500 percent above melt or higher, depending on the issue.

There is a tax angle for UK investors as well. Gold coins that are legal tender, Sovereigns, Britannias and the rest, sit outside Capital Gains Tax regardless of grade. So the entire premium move on a PF70 Sovereign over a five-to-ten-year hold is tax-free. Scarcity-driven appreciation plus zero CGT is what makes the asset class genuinely attractive.

We work exclusively with NGC and PCGS graded coins at PF68 and above. That keeps the quality bar consistent and concentrates the portfolio in the tier where collector demand and long-term price appreciation actually live.

If you are weighing up graded gold coins and want to talk through which grades and issues fit your goals, the team is happy to walk you through it.