eBay Inc. (NASDAQ: EBAY) saw its shares plunge 9.58% in after-hours trading on Wednesday, despite reporting better-than-expected third-quarter results. The e-commerce giant's stock decline was primarily driven by a disappointing fourth-quarter outlook that fell short of analyst expectations, coupled with concerns over recent regulatory changes affecting cross-border trade.

For the third quarter, eBay reported non-GAAP earnings of $1.36 per diluted share, surpassing the FactSet analyst consensus of $1.33. Revenue for the quarter also beat estimates, coming in at $2.82 billion, up 9% year-over-year and above the expected $2.73 billion. The company's gross merchandise volume (GMV) reached $20.1 billion, exceeding analyst projections of $19.5 billion.

However, eBay's fourth-quarter guidance cast a shadow over the otherwise strong results. The company expects Q4 diluted non-GAAP earnings per share between $1.31 and $1.36, below the analyst consensus of $1.38. Adding to investor concerns, eBay's CFO reported a deceleration in year-over-year volume growth starting in September in key markets importing into the US, following the removal of the de minimis exemption. This regulatory change is expected to have a full quarter impact in Q4, compared to just a single month in Q3, potentially putting pressure on the company's near-term performance.