What: Shares of GoPro (NASDAQ:GPRO) opened 23% lower Thursday, then partially recovered to trade down around 16% as of 10:30 a.m. EST after the action camera specialist released disappointing preliminary results for its holiday quarter. And in yet another sympathetic move, shares of video processing chip supplier Ambarella (NASDAQ:AMBA) also plunged more than 11% in early trading.

So what: GoPro won't release its official results until early next month. But for now, it expects revenue to be roughly $435 million for the fourth quarter, marking a 31.4% year-over-year decline, and a significant reduction to GoPro's already disappointing guidance provided in October for revenue in the range of $500 million to $550 million.

Analysts, on average, anticipated revenue would decline 19.3% year over year to roughly $511.9 milion.

GoPro primarily placed the blame on slower-than-expected sell through at retailers in the first half of the quarter, which led to lower sales of its capture devices. GoPro's expected top line was also negatively affected by $21 million for price protection related to its decision to drop the price of its new HERO4 Session camera by another $100 in December.

Meanwhile, even as Ambarella works to diversify its revenue streams, Ambarella investors are no stranger to watching their stock move in lockstep with GoPro -- especially considering Ambarella last quarter blamed its own weaker-than-expected guidance on near-term headwinds in the wearable sports camera market GoPro dominates. If GoPro's woes have intensified in the crucial holiday season, it's hard to blame Ambarella investors for fearing the worst.

Now what: At the same time, this shouldn't be entirely surprising. I even suggested GoPro may have had a rough start early in the season after it reduced the HERO4 Session's price for the second time since its launch in July, and warned it would likely incur charges for price protection and market development funds similar to the $19 million hit it took in the previous quarter.

But the sheer gravity of GoPro's shortfall is (unpleasantly) surprising, so I can understand why the market was willing to so violently bid shares of both GoPro and Ambarella down on Thursday.

On one hand, I'll admit I'm much more tempted by Ambarella as an investor given the fact it is increasingly agnostic about where its chips end up, especially with shares trading at a mouthwatering 14.9 times trailing 12-month earnings and 12.5 times next year's estimates. As for GoPro, on the other hand, I'd like to listen for additional perspective from GoPro's official call a few weeks from now before making any decisions on how to move forward.

Steve Symington has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Ambarella and GoPro. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.