Earlier this month, my friend Hugo Salinas Price emailed an interesting story about a single gold coin that that he still holds dearly.

Story of a Gold Coin by Hugo Salinas Price

As I was shuffling papers in some old files, I came across a slip of paper on which I had written down the price I had paid for a Mexican $50 gold peso coin: 717 Mexican pesos.

Judging from the price, I figure that the purchase was made sometime in 1972, when the price of a Troy ounce of gold was $46 dollars. The Mexican $50 gold peso coin contains 37.5 grams of pure gold, and 37.5/31.1 grams per Troy ounce, is 1.206: so there is 1.206 times more gold in a Mexican $50 gold peso piece, that in a Troy ounce of gold.

Thus, $46 dollars per ounce x 1.206 = $55.48 dollars as the value of the gold in the $50 gold peso coin, in 1972.

The rate of exchange Dollar/Peso in 1972 was 12.50 Mexican pesos per dollar, so $55.48 US x $12.50 = 693.50 pesos. I paid 717 pesos, because gold coins are always sold for a small percentage more than the price of bullion gold; in this case, the surcharge was for 3.4%.

The international price of an ounce of gold, as of November 30 was $1,222.10 dollars. The rate of exchange was at 20.40 Mexican pesos per dollar. So today’s price of the Mexican $50 gold peso coin should be close to $1,222.10 x 20.40 x 1.206 = 30,067 pesos. The quote this morning is: 30,890 pesos.

So my investment of 717 pesos, made 46 years ago, has turned into an investment worth 30,890 pesos today. Looks like a good investment.

But there’s a lot more! Because back in 1993, our President Salinas de Gortari chopped three zeroes off the rate of exchange. So actually, the 717 pesos I invested turned into 30,890,000 of the old pesos!