The reverse of an accumulator. More specifically, it is a structured product that involves investors taking on the obligation to sell a certain number of shares or currency on a regular basis at a fixed price. To that end, the investor writes a call option to the counterparty, with the obligation to sell a fixed number of underlying assets on a regular basis at the strike price. Therefore, decumulators don’t give the option to either party to refrain from exercising. The strike price is typically settled on a periodical basis, and hence the investors are said to be decumulating holdings in the underlying stock over time to maturity.

Investors buy decumulators (or forward decumulators, also) on the expectation that a certain stock will trade within a specific price range, in a bear market, during the term of the contract. This range is bound by the strike price and a barrier price (usually a knock-out that triggers termination if the underlying price goes below a threshold). On the other side, the issuer sells a decumulator in the hope that the underlying will exceed the strike price.