A boundary instrument is a binary options tool through which a trader needs to speculate on whether a certain asset will arrive at a rate that is inside or outside of a predetermined extent of values by the expiry time of the option.

A usual case of conventional binary options trading revolves exclusively around speculating on whether the expiry price of an underlying asset will be higher or lower than the strike price, by the end of a specific time frame.

Trading boundary instruments not only revolves around trading within a specific time frame, but it also involves speculating on whether or not the expiry price will be within a specific range of values.

A boundary instrument is not entirely different, however. Both trading methods still have a predetermined payout rate in the event of a win, and the trader will lose the investment amount in case of a loss in both scenarios.

An example of a boundary instrument trade involves placing a trade on a certain asset with a target price hypothetically varying between 1.35282 and 1.35211. If the option is in or out of that boundary, the trader wins or loses accordingly.