The government currently is selling the gold-coin proofs at a 25% markup over per-ounce gold prices, a premium that can run as high as $360 per coin. The silver coins carry a more than 200% premium over market silver prices.

That might be well worth it for coin collectors and hoarders-or for stashing in a post-apocalypse bunker along with the guns and freeze-dried macaroni. But some unhappy investors have deposited them into retirement accounts, where the shiny gold and silver coins have performed like lead sinkers.

Paul Rumage, a 64-year-old retired software engineer from Michigan, said he was looking for a haven from stocks for his individual retirement account in 2013. A private dealer persuaded him to buy 45 four-coin sets of American Eagle gold proofs, and 979 ounces of silver Eagle proofs, records show.

The U.S. Mint does operate a bit like a coin dealer. Salespeople answer phones. An online store, with a pop-up chat window, adorns the website. Customers can sign up to have annual proof sets charged to their credit cards.

Mint profits on gold Eagle proofs hit nearly 18% last year. Net profits on the Silver Eagle proofs were even better, reaching about 41% last year.

The Mint transfers its profits to the Treasury's General Fund. "We are not in it to make money," said Kristie McNally, the Mint's chief financial officer.

Mint officials said they pitch proof coinage as collector's items, not investments. But Congress kept the door open to putting the coins into retirement account investments a few years after banning other collectible items in 1981.

Nonetheless, Jeffrey Christian, a precious-metals investment adviser, said he steers his clients away: "It's sort of like buying a car and driving it off the parking lot. It will have an immediate depreciation."

To read the complete article (subscription required), see:
U.S. Mint's Gold and Silver Coins Turn to Lead for Some Retirement Investors (https://www.wsj.com/articles/u-s-mints-gold-and-silver-coins-turn-to-lead-for-some-retirement-investors-1511720285)