What happened 

Shares of National Instruments (NATI), an instrumentation hardware and software products company, were tumbling today after the company reported its first-quarter results. National Instruments' earnings beat Wall Street's consensus estimate, but revenue was below analysts' expectations.

The tech stock was down by 11% as of 12:36 p.m. ET. 

So what

National Instruments' first-quarter non-GAAP (adjusted) earnings per share were $0.41, up from $0.32 in the year-ago quarter, and easily beat analysts' consensus estimate of $0.22 per share. 

A person looks at a phone with concern.

Image source: Getty Images.

But the company's first-quarter sales of $385 million, while up 15% from the year-ago quarter, fell far below Wall Street's expectation of $402.7 million. 

The company's CFO, Karen Rapp, said in a press release that National Instruments continued to strengthen its competitive advantages and scale its business in the quarter, adding, "Our strategy proved to be resilient as we navigated lack of component availability and the widely publicized logistics challenges facing our industry in the first quarter." 

Other highlights for the company's quarter included record orders that were up 27% from the year-ago period and a 40% jump in orders in the company's Americas regions. 

Now what 

But investors may have been disappointed with the company's guidance for the second quarter. National Instruments' management said that earnings will be in the range of $0.25 to $0.39, compared with Wall Street's consensus estimate of $0.31 per share. If the company's earnings come in at the low end of guidance, they'll fall below analysts' average estimate. 

Additionally, management said that second-quarter revenue will be between $370 million and $410 million, which is below analysts' average estimate of $421.7 million. 

With the company's mixed results for the first quarter and revenue guidance that fell below analysts' expectations, it's not all that surprising that National Instruments' stock is sliding today.