The juxtaposition of the Bollinger Bands with the price structure has caught my attention ahead of the weekend. Let's notice that since Wednesday's peak at 1075.75, which reversed from just beneath the upper BB, the S&P 500 emini price declined directly towards the rising 20-day moving average, which represents the mid-point between the upper and lower BBnds. Within a bull trend accompanied by rising momentum (RSI), it is typical of a decline to hold in and around the 20 DMA and then turn to the upside to continue to higher-highs. Such was the case during April, May and then again from mid-July to the present.

Notice, however, what happened during the 4-week period between June 5 and July 8, when the emini S&P hit the top BB, reversed and plunged beneath the rising 20 DMA to the lower BB, accompanied by a falling momentum RSI gauge.

The decline amounted to about a 9% correction. This week's downward reversal from the upper BB has plunged to test the rising 20 DMA so far.

Given the sharply falling momentum RSI gauge, might the emini S&P and the S&P 500 Depository Receipts (SPY) for those following the ETF -- be vulnerable to downside continuation to test the lower BB, now 986? We shall find out very soon, but my work argues that just such a technical set-up is facing traders.