(Bloomberg News) Gold reached a new milestone in its role as an investment haven, with the leading exchange-traded fund that tracks bullion surpassing an S&P 500 index-tracking fund as the biggest ETF by market value.

SPDR Gold Trust's market capitalization rose to $76.7 billion on Aug. 19, according to the most recent data compiled by Bloomberg, as the metal topped $1,881 an ounce for the first time. SPDR S&P 500 ETF Trust, which has been the industry's largest exchange-traded fund since 1993, stood at $74.4 billion, now 3.1 percent smaller. At the start of the year, the Standard & Poor's 500 index-tracking ETF was 56 percent larger.

"Gold has become the portfolio antidote for the global financial crisis," James McDonald, chief investment strategist at Northern Trust Corp., the Chicago-based custody bank and money manager, said in an interview.

The metal is up 32 percent in 2011, which would be its 11th straight year of gains, while the S&P 500 Index, a benchmark of the biggest U.S. stocks, has lost 9.5 percent including dividends. Investors have accelerated the retreat from equities on concerns that European countries will struggle to repay their debts and that the U.S. economy is weakening under the strain of unemployment above 9 percent, falling home values and a decline in consumer confidence.

Multiple Investor Preferences

"We are seeing some lasting asset-allocation shifts to gold, including by central banks, as well as some safe-haven flows that could well be reversed in the months ahead," said Mohamed El-Erian, chief executive officer of Pacific Investment Management Co., the Newport Beach, California-based manager of $1.3 trillion in assets.

"The dramatic surge in demand for gold reflects the aggregation of many investor preferences -- for example, from those seeking shelter from lower stock markets to those protecting against currency debasement by central banks," El- Erian wrote in an e-mailed response to questions.

Gold underperformed U.S. stocks in the 1990s in an era of deregulation, Frank Holmes, chief investment officer and CEO of San Antonio-based U.S. Global Investors Inc., said in an interview. That trend started to reverse in 2002 as government regulation increased, and accelerated with the Dodd-Frank rules instituted after the financial crisis of 2008, Holmes said. Rising demand from emerging economies such as India and China has also contributed to higher prices of the metal, he said.

Fear, Love

"We're on a hyper-speed of regulation, and that's not the best thing for the stock markets," said Holmes, who oversees more than $3 billion in funds including those that invest in gold-mining stocks. "The rise of China and India has set up a different dynamic for gold, so you're seeing the fear trade as well as the love trade."