Crypto glossary
OCO order (one cancels the other)
An OCO order links two orders so that when one fills the other is cancelled, typically a take-profit above the price and a stop-loss below it.
OCO stands for one cancels the other. The trader submits two orders at once, most often a limit order to take profit at a higher price and a stop-limit order to cut the loss at a lower one. Both wait on the exchange, and as soon as one executes, even partly, the other is withdrawn automatically.
The main appeal is that a position gets both an exit target and a safety net without the trader watching the screen. That matters in a market that trades 24 hours a day, where a move can happen overnight. Major spot exchanges offer OCO as a standard order type, and derivatives platforms provide similar take-profit and stop-loss brackets attached to a position.
OCO orders inherit the limits of their parts: the stop leg can still fail to fill in a gap, and both legs usually lock the funds or coins they would use. They also cover only one position, so changing its size means rebuilding the pair.
Example
After buying ETH at 3,000 dollars, a trader places an OCO with a sell limit at 3,600 and a stop at 2,700. ETH reaches 3,600 first, the profit order fills and the stop vanishes from the book.