ProShares, the exchange-traded fund (ETF) arm of ProFunds, launched four additional ETFs on the market today.  The new ETFs offer investors leveraged (2x) short exposure to four major market indexes: the Dow Jones Industrial Average, Nasdaq-100, S&P MidCap 400 and S&P 500.  If those indexes rise 1 percent, the complimentary leveraged short ETF should fall by 2 percent, and vice-versa.  The funds are branded as "UltraShort" ETFs, and trade on the American Stock Exchange under the following tickers:

UltraShort QQQ^® ProShares:  QID

UltraShort S&P 500^® ProShares: SDS

UltraShort MidCap 400 ProShares: MZZ

UltraShort Dow 30^®  ProShares: DXD

The launch comes less than a month after ProShares debuted its first eight ETFs, including four offering leveraged (2x) long exposure and four offering straight (1x) short exposure to the same market indexes.

"Because UltraShort ProShares offer built-in magnified short exposure to an index, investors can 'go short' with a single ETF trade," said Michael Sapir, CEO of ProShare Advisors LLC. "Whether the strategy is to capitalize on a trend or hedge against the risk of a decline, magnified exposure means the investor can commit half the dollars to potentially obtain the desired level of exposure. And, while both gains and losses are magnified, unlike other shorting strategies, the investor can't lose more than the original investment."

While active traders will form a large constituency for the new funds, the efficient hedging aspect certainly will appeal to financial advisors and sophisticated investors as well.  Many advisors expressed dismay in June when the leveraged short funds did not launch alongside the original eight ProShares ETFs, as they saw the leveraged short funds as among the most attractive of the new products.

"Buying a double short fund allow for an efficient way of reducing exposure with out having to sell too much stock," said Roger Nusbaum, an investment advisor with Your Source Financial. "A 10 percent weight, tracking error and other flaws notwithstanding, can reduce net exposure by 20 percent. That combined with 15-20 percent in cash gives the chance to miss a big chunk of a large decline, if that is what is coming. If buying a double short fund turns out to be wrong because the market has a big rally, the portion hedged gets smaller as the fund's price declines."

The new funds charge 95 basis points per year in annual expenses, far below the comparable expense ratios for leveraged short open-end mutual funds.

The original ProShares ETFs have already become major hits with investor - or, rather, with traders - with the initial eight funds trading a combined 1 million shares per day this week.  The leveraged long funds have witnessed the bulk of that volume, with the UltraQQQ (QLD) leading the pack; the short funds have seen comparable less volume.  Don't be surprised, however, if the leveraged short funds match or exceed the leveraged long funds on the volume side of the equation.  The funds represent the first easy way for equity investors to make leveraged short bets on the market, and given the current market uncertainty, you can bet that many are going to do just that.