The top-performing ETFs during July were an unusual mix. Some of the best showings were turned in by ETFs that were being taken to the woodshed not all that long ago. The volatility present in the equity markets is certain to make the task of predicting the top ETFs for August an almost impossible challenge. With that said, here are four top ETFs from the last four weeks.

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Re-energized Effort

During July, the Claymore/MAC Global Solar Index (NYSE: TAN) shined brightly as it rose 16.1%. This move upward comes on the heels of a tumultuous start to the year that still leaves this ETF 22.6% below where it started. The recent upswing in crude prices has only added to TAN's rally.

Comprising 9.9% of TAN, the top holding of this ETF is the solar module manufacturer First Solar (Nasdaq: FSLR). Investors had grown bullish on First Solar going into the company's earnings release, which topped analysts' estimates on July 29. Many of TAN's holdings have yet to report their earnings, so where this ETF goes from here will depend heavily on the remainder of these companies' results in the coming weeks.

While clean energy has stolen the spotlight during the past four weeks in the ETF world, the SPDR S&P Oil & Gas Equipment & Services ETF (NYSE: XES) has quietly racked up an impressive 10% gain. This fund is balanced between 25 companies, many of which have ties to the offshore drilling industry. A healthy turnaround from XES would seem to indicate that there are enough investors out there who believe that the sell-off related to the BP oil spill may have been overdone.

The Ascent Of The Ag Play

The Market Vectors Agribusiness ETF (NYSE: MOO) climbed 12% in the past month. Agriculture stocks in general have been bid up in price this summer as the wheat harvest in Russia is projected to be down sharply due to a prolonged drought. World corn production is also expected to come in slightly below forecast.

MOO has 44 holdings; however, more than 40% of this ETF is weighted among the top five holdings. It is really not a bad way for individual investors to play the long-term agriculture theme while eliminating single-stock risk. (Learn more about diversification; see Introduction To Diversification.) Despite this fund's recent strength, it is still down 6.7% on the year.

One other ETF that has come on like gangbusters this past month is the iShares MSCI Spain Index (NYSE: EWP). Shares of EWP have rallied an astounding 25% over this time period. Spain was a focal point of concern earlier in the year as the European debt crisis hit full force. Lately, however, the country's debt auctions have done better than may have been expected, and this ETF is quickly making up lost ground.

The Bottom Line

It is not that often that investors will see a month where both solar and oil/gas ETFs move in the same direction. This occurrence will make it all the more interesting to see whether the recent breakout by solar stocks turns out to be merely a bounce off of the bottom or a sustainable upward trend. Going forward, the clean movement is likely to progress in fits and starts, but this past month was huge for investors with money in this market area. (Learn more about the ins and outs of ETFs; see our tutorial Exchange-Traded Funds.)

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