Here is a chart of the S&P 500 in weekly data. Note that the market easily and repeatedly breached the lower green bands during the decline, so we should not assume that these bands provide reliable guidance for buying or selling. The recent advance has moved the market the full distance from lower to upper bands, however, which typically does not go uncorrected.

The following chart may look the same as the above chart. But it is from April 1930.

The market recovered by an almost identical percentage following the 1929 crash, peaking in April 1930, after which it suffered a subsequent decline to fresh lows. The point here is not that the same outcome will necessarily follow in this instance, but that we would be remiss not to consider the fact that investors were equally cheerful in early 1930, when the front page of the  Wall Street Journal featured an article entitled “A Turn of the Tide Near” assuring investors: "It cannot be imagined that the wholesale failures and interest defaults characteristic of earlier depressions will now be repeated. Confidence in our banking system wholly precludes the money panics of former eras."

Here is the same picture, in monthly data as of Friday's close. Note that in this case the moving averages cover a longer period. So you'll note that after last year's sharp losses, the market has recovered to its 20-month moving average (the middle red line).

The following is the corresponding picture from April 1930.

As well as the rest of the story.

Again, none of this should be taken as a forecast. Rather, it should be considered as a warning that we should not infer too much information content from an advance borne of a steeply oversold condition, especially once that oversold condition has been fully cleared but the underlying debt problems have not.