The GB200 Rare Coin Index showed a year-on-year 6.2% increase in 2015, outperforming the FTSE100 which lost 4.9%.
Over the last ten years the coin index, which is put together by Stanley Gibbons, has achieved a compound annual growth rate of 11.4%.
The most valuable coin in the index, the 1703 Anne Pre-Union Type Gold Five Guineas, rocketed up £50,000 to £375,000.
The Rare Coin Index is a representative sample of 200 rare British investment-grade coins. The values are taken from the independent Spink catalogue of English coins which tracks the performance of the asset class as a whole, as well as individual pieces.
Highlighted in 2015 was the 1738 George II Gold Five Guineas, which increased by 50% to £45,000. Another standout was the 1820 George III Gold Five Pounds which achieved the biggest increase, growing £75,000 in value.
Stanley Gibbons recently sold one of Britain’s rarest coins, an Edward VI “Boy King” gold sovereign of 30 Shillings, to an investor in Asia for £250,000.
Managing Director of Stanley Gibbons Investments Keith Heddle said: “Coins are a classic heritage investment, with more than two and a half millennia of history, tangibility, desirability and strong investment growth. With interest rates still at record lows, these alternative assets can provide not only an excellent return on investment, but are also much more enjoyable to own than a share certificate or a unit in some fund.”