Inverse and leveraged indices

main article: Alternative indices

Inverse and leveraged index methodologies

 * S&P 500 Inverse Daily Index
 * S&P 500 2x Inverse Daily Index
 * S&P 500 2x Leverage Daily Index
 * S&P U.S. Indices Methodology

Articles

 * Warning: Leveraged and Inverse ETFs Kill Portfolios Paul Justice, Morningstar, 1/22/09
 * Research note: Why leveraged ETFs can pack a surprise, Vanguard Investment Counseling & Research 6/22/09