EBay (EBAY) shares tumbled Thursday, a day after the online marketplace gave weaker-than-expected guidance for the key holiday shopping period.

The company sees fourth-quarter adjusted earnings per share (EPS) of $1.17 to $1.22 and revenue of $2.53 billion to $2.59 billion. Analysts surveyed by Visible Alpha were looking for $1.21 and $2.58 billion, respectively.

In the third quarter, adjusted EPS came in at $1.19, with revenue up 3% year-over-year to $2.58 billion. Gross merchandise volume (GMV) rose 2% to $18.31 billion. All three exceeded forecasts.

Jefferies Says 'Cracks Starting To Form'

However, Jefferies analysts wrote in a note to clients that they are "reviewing our model" after the results, warning that "cracks" were "starting to form." They noted that "failing to deliver a meaningful acceleration in 4Q GMV would raise questions around the durability of growth and cause us to grow more cautious." Deutsche Bank analysts added that "tepid GMV growth outlook rattles confidence" in eBay's growth.

Despite today's 8% drop in late-morning trading, shares of eBay have added about a third of their value this year.