By Yaron Steinbuch

Gold bars stamped with fake logos of major refineries have been circulated into the global market and landed in the vaults of JPMorgan Chase & Co. — part of a plot to launder smuggled or illegal specimens of the precious metal, according to a report.

Bars worth at least $50 million stamped with the logos of Swiss refineries that did not produce them have been identified by all four of the country’s top gold refiners in the last three years, Reuters reported.

They have been found in the vaults of JPMorgan, one of the major banks at the center of the market in bullion, senior executives at gold refineries, banks and other industry sources told the news outlet.

Four executives told Reuters that at least 1,000 of the bars have been found — a small share of output from the gold industry, which produces about 2 million to 2.5 million such bars every year.

But the forgeries are sophisticated, so thousands of additional ones may have gone undetected, according to the head of Switzerland’s largest refinery.

“The latest fake bars … are highly professionally done,” Michael Mesaric, chief executive of refinery Valcambi, told Reuters, adding that there are “way, way, way more still in circulation.”

Blocks of cheaper metal plated with gold are relatively common in the industry and are often easy to detect, but the forgeries in these cases are more subtle — the high-purity gold is real, with only the markings faked.