Gold-backed exchange traded funds (ETFs) added 623 tonnes of the metal worth $34 billion to their stockpile from January to May, exceeding in five months every full-year increase on record, the World Gold Council said on Thursday.

In May alone, the increase was 154 tonnes, it said.

Many investors think gold is likely to hold or increase its value as the fallout from the coronavirus outbreak devalues other assets.

Gold prices are up 13% this year at around $1,700 an ounce. Though demand from investors has been strong, sales of jewelry and gold bars and coins in Asia have plunged, preventing prices from rising further.

ETFs store gold on investors' behalf.

The biggest annual increase in ETF holdings is during 2009, during the financial crisis, when they added 591 tonnes, the World Gold Council said.

Its numbers show that by the end of May this year, gold-backed ETFs held 3,510 tonnes of gold worth $195 billion.