In July, the best-performing exchange-traded funds bet either against commodities, or on biotechnology stocks.

With the sharp pullback in the price of oil to the $110 level from the $140 level, the UltraShort Oil & Gas ProShares ( DUG) gained 32.24% in July. The fund tracks the inverse of the Dow Jones U.S. Oil & Gas Index with 200% leverage.

The second-best performer, iShares MSCI Turkey Investible Market Index Fund ( TUR), added 25.23% for the month. This index fund, which began trading on March 28, is off to a good start.

Two other hot newcomers with even shorter track records focus on shorting commodities. For July, the PowerShares DB Commodity Double Short ETN ( DEE) is up 23.06%. Over the same period, the PowerShares DB Agriculture Double Short ETN ( AGA) returned 21.70%.

Most of the remaining funds on the list hold biotech stocks like Genetech ( DNA), Amgen ( AMGN) and Biogen Idec ( BIIB).

The best-performing of these biotechnology funds are the SPDR S&P Biotech ETF ( XBI) and the Biotech HOLDRs Trust ( BBH), appreciating 20.10% and 19.75%, respectively.

Climbing out of the abyss, the Regional Bank HOLDRs Trust ( RKH) halved its loss over the last year with a solid, 16.60% performance in July. Top holdings include JPMorgan Chase ( JPM), Wells Fargo ( WFC) and Bank of America ( BAC).

Best Performing ETFs in July
Fund (Ticker) Rating 1 Month Total Return % 3 Month Total Return % Objective
ProShares Ultra Short Oil & Gas (DUG) E 32.24 13.27 Sector - Energy/Natural Res
iShares MSCI Turkey Inv Mkt Idx (TUR) U 25.23 6.45 Non-US Equity
PowerShares DB Commodity Double Sht (DEE) U 23.06 NA Growth - Domestic
PowerShares DB Agri Double Sht (AGA) U 21.70 NA Growth - Domestic
SPDR S&P Biotech ETF (XBI) B- 20.10 25.30 Sector - Health/Biotechnology
HOLDRS Biotech (BBH) C+ 19.75 26.56 Sector - Health/Biotechnology
First Trust AMEX Biotechnology (FBT) C- 17.29 15.57 Sector - Health/Biotechnology
HOLDRS Regional Bank (RKH) D+ 16.60 -14.22 Sector - Financial Services
iShares Nasdaq Biotechnology (IBB) C+ 15.70 14.80 Sector - Health/Biotechnology
PowerShares Dynamic Biotech&Genome (PBE) C- 15.65 12.13 Sector - Health/Biotechnology
Source: TheStreet.com Ratings

For an explanation of our ratings, click here.

Kevin Baker became the senior financial analyst for TSC Ratings upon the August 2006 acquisition of Weiss Ratings by TheStreet.com, covering mutual funds. He joined the Weiss Group in 1997 as a banking and brokerage analyst. In 1999, he created the Weiss Group's first ratings to gauge the level of risk in U.S. equities. Baker received a B.S. degree in management from Rensselaer Polytechnic Institute and an M.B.A. with a finance specialization from Nova Southeastern University.

More from ETFs

What Bad Weather? Kohl's Shares Spike as Same-Store Sales Jump

What Bad Weather? Kohl's Shares Spike as Same-Store Sales Jump

Listen: Here's What You Need To Know About ETFs Today (Hint: They're on Fire!)

Listen: Here's What You Need To Know About ETFs Today (Hint: They're on Fire!)

Bitcoin Today: Bears Rear Their Heads as Prices Continue Downward Spiral

Bitcoin Today: Bears Rear Their Heads as Prices Continue Downward Spiral

Cannabis Stocks Are Screaming Sells After Seeing This Deal: Doug Kass Insider

Cannabis Stocks Are Screaming Sells After Seeing This Deal: Doug Kass Insider

60 Seconds: What's the Difference Between an ETF and a Mutual Fund?

60 Seconds: What's the Difference Between an ETF and a Mutual Fund?