A hybrid debt instrument that is linked to the equity markets. Equity-linked securities can be in the form of a single stock, a group of stocks or an equity-based index, such as the S&P 500. The return on investment is dependent upon the performance of the underlying equities that are linked to the security. This type of security will often offer a guarantee of principal plus perhaps a small gain in return for a reduced payout of equity gains. Taobiz explains Equity-Linked Security - ELKS Equity-linked securities first appeared in the 1990s and have been offered in the form of annuities, mutual funds and CDs. Most equity-linked securities will limit the equity gains that their investors can realize, either in the form of a reduced percentage of gains (such as 70% of all gains with no limit), or an absolute cap (meaning that the investor gets 100% of the gain up to a certain amount each year in total return, such as 10%). For example, an investor with a 70% cap will see $7,000 of gain from a $100,000 investment if the underlying equities post a 10% gain for the year. However, the same investor with the same investment amount in a security with a 10% cap will only see the first $10,000 of gain in a year even if the underlying equities rise by 50%.