What happened 

Shares of Harmonic (HLIT 14.26%) were tumbling this morning after the company reported its fourth-quarter and full-year 2021 results late yesterday. While Harmonic's revenue and earnings figures were better than expected, investors weren't happy that earnings fell on a year-over-year basis and that 2022 guidance is below Wall Street's expectations.

The tech stock was down by 13.2% as of 11:45 a.m. ET. 

So what 

Harmonic, which designs, manufactures, and sells products and systems that enable network operators to deliver broadcast and on-demand video services, reported fourth-quarter non-GAAP (adjusted) earnings per share of $0.16, which beat analysts' consensus estimate of $0.13 per share for the quarter. Additionally, the company's total sales for the quarter of $155.8 million surpassed Wall Street's expectation of $149 million. 

A person in business attire looking at a smartphone and holding their head in their hand.

Image source: Getty Images.

Harmonic CEO Patrick Harshman said in a press release that the company "ended 2021 with exceptional quarterly results, including record revenue and bookings" and it's on "a strong foundation for sustained momentum as we enter 2022." 

But investors appeared to be disappointed that the company's non-GAAP earnings per share of $0.16 was below the $0.20 per share in the year-ago quarter.  

Additionally, investors may be focusing their attention on Harmonic's guidance for fiscal 2022. 

Management said earnings per share is in the range of $0.26 to $0.40, which means it could fall far below analysts' consensus estimate of $0.49 per share. 

Now what

While Harmonic delivered fourth-quarter results that surpassed Wall Street's expectations, the fact that the company's non-GAAP earnings fell from the year-ago quarter worried some investors today. 

Investors may want to keep an eye on whether this is a temporary drop or part of a larger pattern for the company. In either case, selling a stock based on the results of one quarter typically isn't a good approach to long-term investing.