It has been a crazy couple of days for Qualcomm (QCOM - Get Report) . Even though the stock is well off its session highs and now 52-week highs of $82.50, the stock is up massively over the past two trading sessions.

This would have been a nasty stock to be short and been on spring break for. Shares were muddling along on Tuesday before exploding higher in midday trading after Qualcomm and Apple (AAPL - Get Report) came to a settlement agreement.

Qualcomm stock went from $58 around 2:30 p.m. ET on Tuesday to $70.52 by the close 90 minutes later. Shares closed higher by another 12.25% to $79.08 on Wednesday, even after the pullback from the highs, and are now up around 35% for the last two days.

What do investors do with a rally like that?

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Trading Qualcomm Stock

Five-year weekly chart of Qualcomm stock.
Five-year weekly chart of Qualcomm stock.

This is a five-year weekly chart of Qualcomm stock. Long-term support near $47.50 is pretty evident, while a multi-year trendline (blue line) is also in play. At one point, Qualcomm used this trendline as support, but over time it had turned to resistance. While Wednesday's continuation initially lifted QCOM over this mark, it has since fallen back below it.

So what now?

Until Qualcomm can clear this level on the upside, it will continue to act as resistance. Also worth pointing out is the relative strength index, or RSI. Now, the RSI shouldn't be used to make a thesis -- that is, justify a long or short position -- but rather, used as one of many metrics to anchor one's decision.

Case in point, a stock can stay overbought or oversold for much longer than investors sometimes assume. Meaning that buying an oversold stock for a bounce may not occur, and more relevant in this case, shorting a stock with an elevated RSI may not result in much downside.

Each time over the last three years that Qualcomm stock sported an RSI north of 70 (purple arrows), shares stalled out. Notice that this doesn't mean the stock plunged. Eventually it did decline, but not because of the RSI. In two of those three cases, the stock actually consolidated sideways for several months. I wouldn't be surprised to see Qualcomm stock consolidate between $70 and $80, before possibly moving higher. 

Provided the stock can't push through current resistance and establish a new trend, I want to see Qualcomm stock stay north of Tuesday's close, just over $70.50. Even though it would be giving up a lot of the recent gains, it would still keep this up-move intact. With the good news involving Apple, I don't suspect too much downside in Qualcomm stock over the short term. Below $70 would cause concern, though.

Holding the prior highs near $75 would be more encouraging. Should Qualcomm rally, see that it holds the topside of its trendline. 

This article is commentary by an independent contributor. At the time of publication, the author had no positions in the stocks mentioned.