ETF Securities said Monday that its three gold exchange-traded products increased their bullion holdings by 6.1% in the previous week, according to Reuters. The U.K.-listed funds, including Gold Bullion Securities and ETFS Physical Gold, held 7.989 million ounces of bullion on Friday vs. 7.53 million ounces on Aug. 21.

The increased holdings are a result of record capital inflows: In the past week, ETFS Physical Gold received new investments of $646 million, the company said last week.

The company also said last week that its U.S.-traded ETFS Silver Trust (NYSEArca: SIVR) product has expanded its assets under management to over $100 million since listing on July this year. The fund is up 5.8% since inception. “Investors are becoming increasingly bullish towards silver,” the company said.

The increase in bullion holdings of ETF Securities’ gold funds and the expanding AUM of SIVR come at a time when regulators are looking to clamp down on commodity ETFs. In recent weeks, commodity ETFs that use futures contracts have stopped creating new shares in fear of hitting position limits imposed on them by the Commodity Futures Trading Commission, forcing them to trade like closed-end funds. (See related story here.)

While gold ETFs have not undergone the same kind of scrutiny as their commodity peers since they hold physical assets, some investors fear that their expanding dominance in the hard assets sector may make them vulnerable to future scrutiny by the Securities and Exchange Commission and possibly the CFTC. (See related story here.)

The expanding popularity of commodity ETFs is evinced by ETF Securities’ rapidly widening net AUM, which have risen 85% in 2009, to $13.1 billion.

-- This report was submitted by IndexUniverse.com's Daniel Harrison.