DEFINITION of Mint Ratio

The mint ratio, or gold/silver ratio, is the price of an ounce of gold divided by the price of an ounce of silver, and is the exchange rate between the two precious metals. It is sometimes used as a proxy for market risk, and whether risky assets are overvalued or undervalued.


Investors trade the ratio by buying gold and selling silver, and vice versa. The relationship between these two precious metals is taken to be a measure of investors’ economic optimism, as the mint ratio is inversely correlated to risk appetite. The mint ratio rises in downturns, for example, because investors often seek out gold in periods of uncertainty and silver tends to underperform because it is an industrial metal.

Traders pay particular attention to the mint ratio when it reaches extremes, because the gold/silver ratio has always been mean reverting. Over the last 100 years, it has oscillated in big troughs, over a wide range from 16.8 to 97.3.

The mint ratio has been highly correlated with the S&P 500 in the last 30 years, and oscillated between 45 and 80. But this relationship broke down in 2013, when the S&P 500 headed upward while the mint ratio soared — suggesting that the move might not be justified by fundamentals. In 2018, the mint ratio had risen to the 80 level, from a low of 35 in 2011. This might suggest that the mint ratio should decline over the next few years but it could go higher, if investors buy gold to protect them from inflation.

The daily relative strength index momentum indicator for the gold/silver ratio is watched closely by traders, as a signal for how one metal will move relative to the other, and whether one is overbought and the other oversold versus the other.

The Mint Ratio is Fixed Under Bi-Metallic Standard

Historically, when currencies were based on gold and silver holdings, the gold/silver ratio was fixed. During the 19thCentury, the United States was one of many countries that adopted bi-metallic standard monetary systems, where the value of a country's monetary unit was established by the mint ratio. But the era of the fixed ratio ended in the 20th century as nations moved away from the bi-metallic currency standard and, eventually, off the gold standard entirely.