The last month has been a roller coaster for investors as they have had to endure a big sell-off in May, followed by a snapback rally to begin June. The heavy volatility has wrecked havoc on everything from stocks to commodities as rumors and news out of Europe have investors on the edge of their seats.

Even with a 4% pullback in the SPDR S&P 500 ETF (ARCA:SPY), there have been a few stocks able to gain ground and make investors happy. Within the S&P 500 the top five stocks come from a plethora of sectors, showing randomness of the current market. The four top stocks are below.

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Dean Foods
Dean Foods (NYSE:DF) was the leader of the S&P 500 over the last month, with a large gain of 29%. The stock is trading at a two-year high, but would need to more than double to get back to the all-time high it set in 2007. The stock was helped by a strong earnings report in which the company beat on both the top and bottom line. That momentum has continued for the food and beverage company that concentrates mainly on dairy products. With a PEG ratio of one the stock has more room to run, based on fundamentals.

SEE: How To Use The P/E Ratio And PEG To Tell A Stock's Future

Online travel company Expedia (Nasdaq:EXPE) has gained 14% over the last month and is now trading at an all-time high. This could be considered somewhat of an anomaly due to a slowdown in the European economy, but at the same time oil prices are falling and that could help travel costs. Strong quarterly earnings that saw international hotel bookings soar also fueled the stock. This stock is clearly a bet on the global slowdown not getting much worse and with a PEG ratio of 1.57 it could still move higher.

Newmont Mining
Gold has begun to rally off multi-month lows and the miners have joined in the gains. Newmont Mining (NYSE:NEM) is a gold and copper mining company that had gold reserves of 98.8 million ounces at the end of 2011 and is based in Colorado. The 12% gain over the last month was fueled by higher gold prices as well as a deep discount price per share. The stock currently trades with a PEG ratio of 0.20, one of the cheapest stocks in the index. The one issue is that the stock will be at the mercy of the price movements in gold over the long-term.

SEE: Guard Your Portfolio With Defensive Stocks

The country's largest retailer, Wal-Mart (NYSE:WMT), also had a strong month, logging a gain of 11%. This is not a big surprise considering money tends to flow into the stock when the overall market is in panic mode. The theory is shoppers will flock to WMT for deals due to a potential looming recession. The stock is just below a 12-year high, trades with a PEG ratio of 1.6, and pays a dividend of 2.4%. A pullback from the highs would be a suggestion before buying.

SEE: 4 Characteristics Of Recession-Proof Companies

The Bottom Line
Typically the leaders one month will not be the leaders in the following month, therefore why look at the best performing stocks? The point is to find where money is flowing and why. The answer last month was into stocks that have reported strong earnings and could be considered recession-proof. All four have the potential for higher prices in the future, but after a strong month, the key is to be patient and wait for a pullback to buy.

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At the time of writing, Matthew McCall did not own shares in any of the companies mentioned in this article.