It stands for equity-linked security; an equity-linked debt issue whose returns are keyed to the performance of a common stock (initially the stock of Digital Equipment Corporation). Equity linked securities (ELKS) are fixed-income debt securities with intermediate term. Interest on each ELK security is payable on a quarterly basis. In the case of ELKS, and unlike ordinary debt, the principal payable upon maturity is not fixed but is based on the price of underlying common stock. The principal amount payable at maturity will be the lesser of two amounts: (1) 135% of the issue price; (2) the average closing price of the underlying common stock for the 10 trading days immediately prior to maturity.

Given that the payoff of an ELK is determined based on the average stock price, this instrument can be viewed as an average-price Asian option.