Precious metals and miner ETFs were the standout performers this week as investors positioned for more economic stimulus from the Federal Reserve and European Central Bank.

Silver ETFs such as iShares Silver Trust (NYSEArca: SLV) and ETFS Physical Silver Shares (NYSEArca: SIVR) were poised for weekly gains of 9%. [Silver ETF Rally Faces Key Test]

Meanwhile, gold ETFs added about 3%. SPDR Gold Shares (NYSEArca: GLD) was the top-selling ETF for the week ended Aug. 22 with inflows of $1.3 billion. [Gold ETF Sees Big Weekly Inflow on 3% Rally]

ETFs that invest in miner shares were also strong this week. Global X Silver Miners ETF (NYSEArca: SIL) and Market Vectors Gold Miners (NYSEArca: GDX) were on track for weekly advances of more than 5%.

ETFS Physical Platinum Shares (NYSEArca: PPLT) rallied on heavy volume in the wake of deadly mine protests in South Africa. [Platinum ETFs in Focus on South Africa Unrest]

In U.S. stocks, however, the S&P 500 was on track to snap its six-week winning streak. In afternoon trading Friday, the blue-chip index was down 0.7% for the week, the Dow slipped 1.2% and the Nasdaq Composite fell 0.4%.

In bond ETFs, Treasury yields declined along with stocks – iShares Barclays 20+ Year Bond Fund (NYSEArca: TLT) rose nearly 3% for the week.

The top three unleveraged ETFs this week were iShares Silver Trust, ETFS Physical Silver Shares and Global X Silver Miners ETF with gains of 7% or more.

The bottom three unleveraged ETFs were Market Vectors Vietnam ETF (NYSEArca: VNM), iPath US Treasury 10-Year Bear (NYSEArca: DTYS) and VelocityShares Daily Inverse VIX Short Term (NYSEArca: XIV) with losses of at least 4%.

In next week’s economic data, look for reports on home prices, pending homes sales, the Federal Reserve’s beige book, factory orders, and personal income and spending.

iShares Silver Trust

Full disclosure: Tom Lydon’s clients own TLT, GLD and SLV.