Negative divergences on the MACD and light volume on breakouts are two important criteria in identifying a possible top. Accumulation requires volume so I'm always suspicious if advances begin to run out of it. In the case of Adobe Systems (ADBE), it has these markers in place just one week before they release their latest quarterly results. I would look for further selling prior to earnings or a possible selloff after results are released. Be very careful if a failed breakout occurs on better than expected results. Here's the chart:
Should ADBE lose its rising 20 day EMA support, where it's held the last three tests, it would appear to be on a crash course with trendline, price and 50 day moving average support in the 87-88 area. Volume has been extremely light in recent trading sessions. That, along with the negative divergence, tells me it's a tired stock and in need of further consolidation or temporary price decline.