What happened 

Shares of Kopin Corporation (KOPN -25.33%), a maker of wearable technology components, were tumbling this morning after the company reported worse-than-expected fourth-quarter 2021 results. 

The tech stock fell by more than 10% this morning and was down by 5% as of 10:45 a.m. ET. 

So what

Kopin reported fourth-quarter sales of $13.2 million -- a decrease of 5.7% from the year-ago quarter. Investors are always disappointed when revenue falls on a year-over-basis, but things looked even worse with the company's earnings.  

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Image source: Getty Images.

Kopin had a non-GAAP (adjusted) loss per share of $0.04 in the quarter, compared to earnings of $0.02 in the year-ago quarter and below analysts' consensus estimate of a loss of $0.03 per share.

The company's defense revenue segment -- which brings in most of the company's sales -- appeared to be the problem in the fourth quarter. Defense sales tumbled 21% year over year, in part because some product shipments were lower in the quarter.

"In the fourth quarter of 2021 shipments of our US Army's Family of Weapon Sight-Individual (FSW-I) program were lower as we completed process enhancements to our line," Kopin CEO John Fan said in a press release.

Now what 

With sales sliding in the company's largest revenue segment and earnings falling below expectations, it's not surprising that some investors sold their Kopin shares today. 

The company didn't release any guidance for the first quarter or full year 2022, which probably didn't help ease investors' concerns about today's quarterly results. 

With Kopin still dealing with supply chain issues, it's likely that investors will be keeping a close eye on the company's financial results in 2022 to see if it can turn around some of the setbacks it's faced recently.