Shares of CBS (CBS) - Get Report   were falling in early trading Tuesday, down about 3% after reporting its quarterly results.

After rallying more than 11% in just a few days, shares were having trouble pushing through a few key technical levels on the charts. While the Tuesday morning pullback is mild so far, a continued decline would put a must-hold support level on the table for the stock.

Unfortunately, it's not clear whether the company's third-quarter earnings report will be much help for bulls.

While earnings of 95 cents a share topped expectations by 2 cents, revenue of $3.3 billion grew just 2.2% year over year and missed analysts' estimates by $70 million.

As other companies like Disney (DIS) - Get Report and Apple (AAPL) - Get Report join the streaming battle with Netflix (NFLX) - Get Report and others, some investors wonder how viable CBS will be in the future, even as it's set to merge with Viacom (VIA) - Get Report (VIAB) - Get Report .

That makes it a perfect candidate for Real Money'sStock of the Day feature. While they comb over the stock there, let's look at the charts here.

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Trading CBS Stock

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As shown on the daily chart above, CBS stock hammered out a bottom at $35 over several days at the end of October. Rallying off those lows, shares ran up through $39 ahead of earnings.

It's natural to see a stock pullback after such a strong burst of bullish momentum in such a short period of time. However, where it pulled back from has caught the attention of some traders.

The 50-day moving average comes into play at $39.38, while the 78.6% retracement sits up at $39.71. While CBS stock didn't technically hit either of these levels, doesn't mean they didn't (or won't) act as resistance. In my view, these marks are resistance until CBS is able to reclaim them. 

Now near $38, shares are setting up in a very interesting manner.

CBS may continue to trade lower into the $36 to $35 range, which would bring up key support. Below $35 and things can get ugly for CBS, as that is the must-hold mark for the stock.

Should CBS stock find its footing and move higher, the combination of the 50-day moving average and 78.6% retracement will be the next key hurdle. Above it puts the $40.50 to $41 zone on the table. Above that and CBS can really harness some upside momentum.

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