Accumulators (aka: share forward accumulators) are financial derivative products sold by an issuer (seller) to investors (the buyer) that require the issuer to sell shares of some underlying security at a predetermined strike price, settled periodically. This allows the investor to "accumulate" holdings in the underlying security over the term of the contract. Sometimes known as "I kill you later" contracts, accumulators typically last for a year or less and terminate early ("knock-out") if the stock price goes above a threshold ("barrier").