If the S&P500, and the other American indexes, are due a down-swing, so also may the Hang Seng index, as the following chart, posted by me today on www.TradingView.com, shows:
Click on image to enlarge.
The Hang Seng index is indicated by the blue graph line. The dotted blue trend lines are the Resistance and Support Lines. The graph is touching the Resistance Line, which usually indicates that a down-swing, back to the bottom trend line, is probably imminent. The shaded area is the range contained within the Bollinger Bands, and the red line is the median position between these bands.
While the drawing of trend lines is intuitive (joining the tops to form a Resistance Line and the bottoms to form a Support Line), Bollinger Bands, invented by John Bollinger, are calculated automatically by computer program using a clever formula and can be interpreted to predict trend reversals as well as swings. The median line is the Moving Average of the security price based on 20 periods, in other words a point on the red line is the average of the price of the security over the last 20 periods, which, of course, keeps changing, or "moving," as time passes. The outer lines are the Standard Deviations from the median line. Widening of the bands indicated increased volatility; "W" shaped bottoms in a graph, without breaking the lower bound, indicate a down-trend coming to an end, while "M" shaped tops, without breaking the upper bound, indicate an up-trend ending.
Since the band is not particularly wide at the present time, the index is shown not to be volatile and the present trend should continue for now.
The recent weak W bottom on the graph suggests that this time the graph may not bounce off the Resistance Line, but continue upwards.
While a graph more often than not bounces off the Resistance Line, the Bollinger Bands suggest that the signal is unclear. I intend to pass this opportunity.