KEY TAKEAWAYS A descending channel is drawn by connecting the lower highs and lower lows of a security's price with parallel trendlines to show a downward trend. Traders who believe a security is likely to remain within its descending channel can initiate trades when the price fluctuates within its channel trendline boundaries. A more potent signal occurs with a breakout, which is when a security's price breaches an established channel's boundaries, either on the upper or lower side.