Haynes, based in Oklahoma City, expects to ship as many as 15 million precious metals coins or bars this year, double last year's figure. The University of Texas Investment Management Co., the second-largest U.S. academic endowment, said April 14 it took delivery of about $1 billion of gold bars.

Another warning sign for the rally may be central banks adding to their reserves for the first time in a generation. Mexico, Russia and Thailand bought about a combined $6 billion in February and March, International Monetary Fund data show. Central banks hold 30,575 tons, equal to about 18% of all the metal ever mined, the data show.

Boosting Holdings

The banks were also boosting holdings in 1980 when gold rose to a then-record $850, only to fall for most of the next 20 years. That high is equal to $2,299 in inflation-adjusted terms, according to a calculator on the website of the Federal Reserve Bank of Minneapolis. Prices tripled from 1999 through the beginning of 2008 as the banks sold more than 4,000 tons.

"Central banks don't have the best track record trading gold," said Malcolm Freeman, managing director of Ambrian Commodities Ltd. in London. He pointed to the U.K., which sold about 400 tons over about a two-year period ending in 2002, getting no more than $296.50 an ounce.

Rising interest rates could also diminish the appeal of gold, which generally earns investors returns only through price gains. At least two dozen nations and the European Central Bank raised rates this year, data compiled by Bloomberg show. The Fed will probably hold its benchmark rate in a range of zero to 0.25% through the fourth quarter, according to the median forecast of 72 economists surveyed by Bloomberg.

Reduced Stimulus

Reduced stimulus may also strengthen the dollar. Fed Chairman Ben S. Bernanke signaled April 27 the bank will keep record monetary stimulus when its $600 billion bond purchase program ends in June, the second round of so-called quantitative easing. The Dollar Index rose 3% since then.

"If we get a rise in the dollar because the Fed is exiting QE2 in June, gold could hit $1,200," said Michael Pento, a senior economist at Euro Pacific Capital Inc. in New York who has correctly predicted the high in gold for the past two years. "It would be a buying opportunity."

The Dollar Index fell to a two-year low of 72.7 on May 4 and was at 75.71 on May 13. It will drop to 73.57 at the end of this year and 70.81 at the end of 2012, according to data compiled by Bloomberg from analysts' forecasts.