Central banks across the globe are in a gold buying rush that has lasted than a decade. That is the longest of gold acquisition by government-run financial institutions in more than half a century.

This time, the motivation of the buyers is quite different from what drove them back in the 20th century as they are worrying. That is the reason why investors should be mindful, including anyone who owns the SPDR Gold Shares (GLD) exchange-traded fund which holds bar at bullion.

In the past decades, gold was bought by central banks because of its vital role in the global financial system. Now, the focus has changed as they choose to buy because they are worried about the stability of Dollar, hence they have been gauged in gold buying rush.

Reporting the position of the Central-bank-gold relationship, Simon Constable, a fellow at the Johns Hopkins Institute for Applied Economics state that “Before the gold standard monetary system was abandoned in 1971, central banks, such as the Federal Reserve or the Bank of England, had to buy and sell gold. Doing so was an essential part of the global financial system that was set up in the closing days of WWII, the so-called Bretton Woods system. As international trade flourished so the need for gold increased. That’s why central banks added a lot of bullion to their reserves in the 1950s and 1960s,

“Over the 16 years through 1965, the world’s central banks added at least 5 million troy ounces of bullion to their gold stash each and every year. Some years the additions were higher than 20 million ounces, according to data from New York-based commodities consulting company CPM Group. That 16-year period may understate the prolonged central bank demand for bullion reserves. Jeff Christian, managing partner of CPM Group, explains:

“[It was] a continuation of a longer-term trend because of gold’s role in currency systems, its use as a denominator for the value of national currencies at the time, and its use in settling international trade settlements,

“It’s worth noting that after WWII gold was set at a price of $35 an ounce and other currencies, such as the British pound, the French franc, or the Japanese yen, had a (mostly) fixed exchange rate with the dollar,

“Eventually, this gold-based system died. Officially, U.S. President Richard Nixon nixed it in 1971 when he stopped countries from exchanging dollars for gold. The period of the late 1960s also coincided with massive military spending by the U.S. due to the country’s entanglement in Vietnam,

“Unofficially, the end of gold’s vital role in trade came in 1966 as individuals started to demand gold in exchange for their dollars, says Christian. Eventually, they were shut out just as the countries were excluded,” Constable has reported.

This is means that since the mid-1960s central banks have sold ‘their mental’. Constable reported that “what this all means is that since 1965, when the gold standard started to look iffy, central banks have mainly sold their metal. In 1966, they dumped more than 45 million ounces, and many years sales were more than 10 million ounces annually,

“Over the period of 1966 through 2007 central banks mainly ditched their gold holdings. That is to say, they sold right up until the global financial crisis really hit home in 2008,

“As the global financial system seized up in 2008 and early 2009, global central banks caught the gold buying rush again. It’s a trend that looks likely to continue,

“Starting in 2008 central banks have continuously added gold to their reserves. At first, the net acquisitions additions were relatively small. In 2008 and 2009, such institutions added 580,000 and 210,000 ounces of the metal respectively, again according to CPM data. Since then the buying binge has accelerated, with around 11 million ounces getting purchased in 2017, with likely a similar amount forecast for this year.

According to data from Bloomberg, Gold futures were recently changing hands at around $1,197 a troy ounce, down from approximately $1,336 a year ago.