A company called ProShares has created several ETFs to address this very issue. Two of its most popular offerings are the UltraShort QQQ, which seeks to return 200% of the inverse (opposite direction) of the NASDAQ-100 Index, and the Ultra Short Dow30 which seeks to return 200% of the inverse of the Dow Jones Industrial Average.
It is important to note that these funds are inverse ETFs. That means that their prices should move in the opposite direction of the targeted index. In other words, if the NASDAQ-100 price is rising, then the targeted price of the UltraShort QQQ would be falling, and vice versa. Additionally, the overall amount of the movement is aimed to be 200%. So, if the NASDAQ-100 lost 5% of its value, the UltraShort QQQ would hypothetically gain 10% if its objective was met.
Thus, both the UltraShort Dow30 and the UltraShort QQQ allow investors to profit from downward movements in the overall stock market without having to maintain a margin account and short individual stocks. Typically, the UltraShort QQQ will be the more volatile of the two investments, reflecting the additional volatility of the NASDAQ-100 as compared to the Dow. With the magnification of the returns via leverage, these two funds can have wildly different days, so investors should fully understand how leveraged ETF work before investing any money.