J.C. Penney fell more than 8 percent on Thursday after a research note from Wells Fargo said the retailer's acceleration is "much less impressive" than it might appear.
The department store chain indicated November comps were up 10.1 percent—in line with Wells Fargo estimates. Wells said that November results "may be as good as it gets" in the the fourth quarter, but cautioned that "many are likely to misread the magnitude of the acceleration."
The note pointed out that the sales are good, but also promotional, as J.C. Penney ratcheted up online promos, transforming a Cyber Monday into a week-long event.
(Read more: Why JC Penney's $1.97 pants could spoil Christmas)
"Now that we are past Black Friday, we are likely to see a lull period until the days leading up to Christmas," analysts wrote.
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Reuters reported that Hayman Capital Management, a hedge fund, told Bloomberg TV on Thursday that it sold its shares in J.C. Penney, though it still holds the retailer's debt.
"We believe J.C. Penney has been burned by the effects of an unsuccessful turnaround strategy, which has created a hole that is likely too deep," Wells Fargo's note said.