Gold ETFs are threatening to slip into negative territory for 2012 as the precious metal’s price falls below a key long-term trend line.

SPDR Gold Shares (NYSEArca: GLD) was down 0.8% Friday afternoon with gold futures trading below $1,600 an ounce. The ETF is down nearly 4% on the week.

Other ETFs that hold gold bullion include iShares Gold Trust (NYSEArca: IAU) and ETFS Physical Swiss Gold Shares (NYSEArca: SGOL).

The pace of the 11-year bull market in gold has increased over time although the metal is trading more than 16% below its Sept. 6, 2011 peak, according to

Over the past eight months gold has “declined more than at any point since 2008 as many investors have opted to park a portion of their investment dollars in dollar-denominated T-bonds as opposed to gold as the European debt crisis continues and China slows,” it noted.