Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Bollinger Bands and TRENDING market
If upper and bollinger bands either converge (both bands are getting more and more close together) or diverge (both bands are getting more and more away from each other), does that mean the market is TRENDING? The answer is no. The divergence or convergence of BB-upper & lower band does not indicate if the market is trending or not. It only indicated if volatility is increasing or decreasing. Or is market trending only in case if both bands, upper and lower, are parallel and at the same time NOT horizontal? The answer is yes. To understand the reason consider that BB is constructed from a central Moving Average along with standard deviation. Upper Band=MA+2*SD, Lower Band=MA-2*SD. A moving average is a trend following indicator and volatility has nothing to do with trend (as SD only measures the price movement around the mean). Which essentially means BB has trend following qualities. The upper and lower bands remain more or less parallel in between band contraction and expansion. Refer below:   You shall see distinctly phases when BB bands are not parallel and are parallel and not horizontal. As mentioned above, when BB bands are expanding or contracting they do not give indication of the trend direction. When they are parallel, close or apart and not horizontal, they provide a good directional bias through the general slope. Though a more effective method to determine trend and its direction is the central MA of BB. Again, refer below:  Here you can see that some portion of the bands are parallel and more or less horizontal. The price action would tell you that the stock is now range-bound as opposed to trending. The primary use of the BB bands are to gauge volatility as @misantroop stated. The primary trend direction is usually derived from the central MA.