While experts aren't too worried about each new milestones, they are starting to freak out about the rapid speed at which prices are hitting them. Gold started the year just above $1,400 an ounce.
Gold prices first crossed the $1,900 mark in after-hours electronic trading Monday. Early Tuesday, prices hit an all-time high of $1,917.90 an ounce, before pulling back to about $1,880.
"Gold could keep working its way higher, but it is starting to look a bit bubbly," said Matt Zeman market strategist at Kingsview Financial in Chicago. "The run-up reminds me of what silver did a few months ago. It climbed steadily week after week, sucked everyone in, and then the whole deck of cards came crashing down."
With investors plowing into gold in droves, the SPDR Gold Trust ETF (GLD), one of the most popular funds for investors seeking exposure to gold, is now the world's largest ETF with nearly $77 billion in net assets. Since 1993, the SPDR S&P 500 ETF Trust (SPY) held the top spot. It boasts about $75 billion in assets, accord to State Street Global Advisors.