Ratings agency Standard & Poor’s in July made the historic decision to cut the US government’s credit rating from AAA to AA+. In a somewhat counterintuitive response, safety-conscious investors flocked to US Treasury bonds in the second week of August, pushing the yields on three- and 10-year notes to record lows.

Much of this money came from equity markets, sending the Chicago Board Options Exchange Volatility Index (VIX)—a measure of the implied volatility of S&P 500 options—to its biggest jump since February 2007

In these unsettled markets, many investors have plowed money into gold, a traditional safe-haven investment. The most recent gold rush has prompted speculation that the popular exchange-traded fund (ETF) SPDR Gold Shares (NYSE: GLD) has little upside left. After all, one rarely makes money by purchasing a security that’s just hit an all-time high.

But there are a number reasons why investors in the yellow metal may still pocket tidy gains.

The Federal Open Market Committee’s Aug. 9 statement emphasized that the central bank may  implement additional policy measures to support the weak economy, opening the door for a third round of quantitative easing. Such a move would increase inflationary pressures, driving more investors toward gold.

The flood of money into Treasuries also makes gold an attractive alternative for investors. Aside from their perceived safety, US Treasury bonds offer little value to investors at these levels. With yields plumbing new lows across the curve, you’re effectively paying the government to hold your money.

Although gold bullion remains a solid investment, the real winners when it comes to skyrocketing gold prices are the producers of the yellow metal themselves.

As gold prices have surged over the past two years, many mining outfits have thrown off their hedge books in favor of selling into the market to realize better prices on their production. With gold now at around $1,800/ounce and the average cost to produce an ounce of gold averaging around $600 for the majors, that equates to about a $1,200 margin on each ounce produced. That’s extremely bullish for the miners’ bottom line.

Market Vectors Gold Miners ETF (NYSE: GDX) is an easy way to achieve passive exposure to a number of gold miners. The fund tracks a basket of about 30 miners whose primary business is mining gold, though you’ll find a handful of more diversified miners in the mix. All of the exchange-traded fund’s (ETF) holdings boast a market capitalization of at least $100 million. You won’t find many junior miners in a portfolio dominated by the likes of Barrick Gold Corp (TSX: ABX, NYSE: ABX), Goldcorp (NYSE: GG) and Newmont Mining Corp (NYSE: NEM)—all of which reported soaring earnings in the second quarter.

While that bias toward the majors does limit the ETF’s potential upside, it also helps lower the fund’s risk profile and dampens volatility. Furthermore, junior miners that are more involved in prospecting might struggle to secure financing in the unlikely event that a second recession takes hold.

The fund does have drawbacks. The ETF’s capitalization-weighted portfolio is extremely top-heavy; its 10 largest holdings account for more than 71 percent of assets. However those 10 names also happen to be among the industry’s most stable companies.

Market Vectors Gold Miners ETF charges a 0.53 percent annual expense ratio, one of the lowest among gold equity ETFs.

Fidelity Select Gold (FSAGX, 800-544-8544) also offers exposure to the mining industry but courts a bit more risk. Manager Joseph Wickwire runs a diversified portfolio comprising roughly 100 positions and shifts assets between junior and senior miners based on his outlook for the gold market.

When Wickwire believes that gold prices are poised to decline, he favors larger, diversified miners. However, when the fund manager is bullish on gold prices, he’s apt to add some speculative fare to the portfolio, though established names currently account for about 70 percent of the fund’s equity exposure.

Wickwire limits volatility by focusing on firms with quality management, sizable reserves and low production costs. A track record of success and an extraordinarily low expense ratio of 0.94 percent–the category average is 1.5 percent—make this fund a winner.

Benjamin Shepherd is editor of Louis Rukeyser’s Mutual Funds and co-editor of Global ETF Profits.