NEW YORK (TheStreet) - J.C. Penney (JCP) shares were in the red on Wednesday, despite posting double-digit gains in comparable sales last month.

Investors are likely realizing what Wells Fargo Securities analyst Paul Lejuez said in a research note, that November comps "may be as good as it gets in Q4 2013" because the November 2012 sales comps at J.C. Penney were down 34% -- the worst comps of the quarter last year.

"Now that we are past Black Friday, we are likely to see a lull period until the days leading up to Christmas," Lejuez wrote in the note. "Keep in mind December comparisons are more difficult that November (which had the Sandy comparison benefit as well) and January is the toughest. Therefore, if the same run-rate holds, reported comps would decelerate from here."

The beleaguered department store chain late Tuesday said comparable store sales jumped 10.1% in November, benefiting from the all-important Thanksgiving and Black Friday weekend sales. J.C. Penney opened at 8 p.m. on Thanksgiving to compete with other retailers, including Macy's (M) and Target (TGT).

It's the second month in a row the Plano, Texas-based company reported positive monthly sales. Last month, J.C. Penney reported its first positive comp data since December 2011.

Despite the strong sales figures, J.C. Penney shares were down 3.1% to $9.80 in mid Wednesday trading.

Lejuez also believes "many are likely to misread the magnitude of the acceleration" in November. "Using 'simple' stack analysis, it appears November accelerated by 700 bps [basis points]," compared to comp sales for the entire third quarter (down 4.8%). "The 'real' math shows it was only 230 bps," Lejuez said. "Still an acceleration to be fair, but much less impressive in our view."

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