There are over 1,800 exchange-traded funds (ETFs) available to investors, and so much choice can lead to paralysis when it comes to choosing the right funds for your portfolio. Leveraged ETFs comprise a small fraction of the available ETFs, and with good reason. These are highly complex investment vehicles with a high-risk, high-cost structure suitable for experienced investors with a high risk tolerance.

Leveraged funds use debt to achieve returns that are typically two or three times that of the index they track. For example, a fund with a 2:1 ratio would match each dollar of investor capital with $1 of invested debt (via futures contracts or other derivatives), which in theory would double the return, less any management fees and transaction costs. If the index achieves a 1% gain, a 2:1 leveraged fund would return 2%. Of course, the opposite is also true: a 1% loss becomes 2% in a leveraged ETF. (See also: Dissecting Leveraged ETF Returns.)

These funds are not generally considered long-term investment options. In fact, most investors limit their exposure to a leveraged fund for a single day or a matter of days in order to capitalize on a positive run of the underlying index. It is important to note that these funds are rebalanced daily, and as a result, performance numbers may not closely track the long-term performance of the underlying index – in this case the S&P 500. If you are interested in exposure to a leveraged ETF, here are four leveraged S&P 500 indexed funds that are outperforming their peers. (See also: Leveraged ETFs: Are They Right for You?)

All year-to-date (YTD) returns are based on the period of Jan. 1, 2017, through July 7, 2017. Funds were selected on a combination of performance and assets under management. All figures were accurate as of July 10, 2017.

ProShares Ultra S&P 500 ETF (SSO)

  • Issuer: ProShares
  • Assets Under Management: $1.88 billion
  • YTD Performance: 17.95%
  • Expense Ratio: 0.89%

This leveraged fund seeks to double the return of the S&P 500 for a single day (from one NAV calculation to the next) using stocks and derivatives.

ProShares Ultra Pro S&P 500 ETF (UPRO)

  • Issuer: ProShares
  • Assets Under Management: $868.5 million
  • YTD Performance: 27.34%
  • Expense Ratio: 0.94%

This ProShares ETF is similar to its sister fund (SSO), but UPRO aims for returns equivalent to 300% of the S&P 500 using swap contracts for leverage. Both funds are rebalanced daily, so multiplied returns may not exactly match the returns of the underlying index over the long term. (For more, see: SSO vs. UPRO: Comparing U.S. Leveraged ETFs.)

The following chart is proof of the power of leverage. UPRO's total return since inception is 1,286%, significantly more than the S&P 500 during the same period.

Direxion Daily S&P 500 Bull 3x Shares ETF (SPXL)

  • Issuer: Direxion Funds
  • Assets Under Management: $562.78 million
  • YTD Performance: 26.96%
  • Expense Ratio: 1.06%

Direxion offers two S&P 500 leveraged ETFs that seek to produce three times the return of the index on a daily basis. Direxion also has a companion fund, the Bear 3x shares, which aims for returns of 300% of the inverse of the S&P 500. (See also: How Do Leveraged ETFs Compound Volatility?)

Bonus: Bearish Leveraged S&P ETF – ProShares Ultra Short S&P 500 (SDS)

  • Issuer: ProShares
  • Assets Under Management: $1.39 billion
  • YTD Performance: -16.35%
  • Expense Ratio: 0.90%

If you're feeling bearish this year despite all evidence to the contrary, this S&P indexed ETF seeks to return -200% of the index returns on a daily basis. (See also: The Long and Short of Inverse ETFs.)

Want to learn how to invest?

Get a free 10 week email series that will teach you how to start investing.

Delivered twice a week, straight to your inbox.