The Pennant is a relatively rapid formation that appears as a small wedge after a steep trend, which develops in the opposite direction: after an uptrend it has a downward slope and after a downtrend, an upward slope. The preceding trend is crucial for the pattern formation and is often called a Pennant pole. The question of the slope of the preceding trend is somewhat controversial: some prefer it very steep, almost straight, while others find those with slope of 45 degrees the most desirable. The wedge that develops in the Pennant is relatively small, thus price action in it is almost immediate compared to other patterns: it usually takes several days to couple weeks for the Pennant to be completed.
Breakouts happen in both directions but virtually all Pennants are continuation patterns, which means that Pennants in uptrend are expected to break out upward and those in downtrend, downward. Pennant performance strongly depends on the initial price change as defined by the Pennant pole: those with price change more than 90% rarely fail. Volume is usually heavy at the pole but declines throughout the formation.