When the investors feel like the stock has reached a peak, lots of them will sell and the stock will start to drop. More and more investors will follow,
leaving it a bearishmarket. Below is an example of a bearish crossover.
You will notice in the bottom center portion of the chart that the MACD crosses
over the signal line from top to bottom, and continues for quite some time.
Even if the MACD itself is increasing, this does not indicate a bullish tendency