Sierra Wireless ( SWIR) lost a third of its value in late trading after the wireless-card maker painted a bleak picture of first-quarter business trends.

Late Wednesday, the Vancouver, Canada, company posted fourth-quarter numbers that missed estimates. Sierra Wireless cited softer-than-expected demand for PC cards, sending its stock down 34%. Shares of rival Novatel ( NVTL) plunged 14% in sympathy.

For the quarter ended Dec. 31, the company earned $7.3 million, or 28 cents a share, up from $1.9 million, or 8 cents a share a year ago, but a penny shy of the Thomson First Call analyst consensus estimate. Revenue rose to $59 million from $35 million, again missing the $63 million consensus estimate.

But the fourth quarter looked downright ruddy compared to the company's first-quarter guidance. Sierra Wireless projected a loss of 35 to 38 cents a share on revenue of about $19 million. Analysts had been expecting a 20-cent profit on revenue of $54 million.

"This is partially a result of lower sales from embedded modules that will not include further shipments to palmOne for the Treo600," the company said in a postclose press release. "We also expect that Q1 demand for PC cards will be lower as a result of channel inventory levels at some of our channel partners that is already sufficient to meet their short term customer demand and the near term impact of increased competition, and resulting loss of market share, in the EVDO PC card market."

Late Wednesday, Sierra Wireless dropped $4.95 to $9.50.