PowerShares DB Base Metals Fund ( DBB) -0.7% DBB's 200-day moving average has proven to be an effective point of resistance. Since it tested this level last week, the fund has suffered a steep multi-day string of gains, pushing it back to its 50-day moving average. It will be interesting to see if this point proves to be one of support. All prices as of 2:13 PM EST. Written by Don Dion in Williamstown, Mass.