Fortinet (FTNT 0.23%) stock is getting crushed following the publication of the company's third-quarter results. The company's share price was down 16.6% as of noon ET Friday, according to data from S&P Global Market Intelligence.

Fortinet published its Q3 report after the market closed yesterday, delivering earnings that topped Wall Street's target and sales that fell short of the market's expectations. More importantly, the company also issued worrying guidance and commentary that prompted an uptick in bearish sentiment.

Wall Street sours on Fortinet stock after Q3

Fortinet posted non-GAAP (adjusted) earnings per share of $0.41 on revenue of $1.33 billion. For context, the average analyst estimate had called for earnings of $0.36 per share on sales of $1.35 billion. Sales in the period were still up roughly 16% year over year, but the performance signaled slowing growth -- and commentary from management confirmed that the near-term performance outlook is significantly weaker than many investors and analysts had anticipated.

Following the Q3 release, Fortinet stock ratings and price target downgrades from multiple high-profile investment firms including Stifel and JPMorgan Chase.

What comes next for Fortinet?

For the current quarter, Fortinet is guiding for sales to come in between $1.38 billion and $1.44 billion -- suggesting roughly 10% year-over-year growth at the midpoint of the target. Meanwhile, the average analyst estimate had targeted sales of $1.49 billion for the period.

The midpoint of the company's guidance range came in roughly 5% lower than the midpoint sales target from analysts, and Fortinet's comments suggest there's a risk that sales could come in at the lower end of its forecast range.

Notably, Fortinet is seeing softening demand for its firewall hardware and services. In turn, the company plans to ramp up investment in security operations, its universal secure access service edge, and secure networking offerings. With a core performance driver seeing its momentum slow and investments into new growth drivers, it's reasonable to expect that sales and earnings performance could be pressured in the near term.