What happened 

Shares of software giant Autodesk (ADSK 5.45%) fell as much as 10% in trading on Thursday after the company reported worse-than-expected financial results. Shares have stayed near their lows most of the day and are down 8.3% at 1:15 p.m. EDT. 

So what

Second-quarter revenue was up 16% from a year ago to $1.06 billion, meeting analyst estimates, and net income was up 18% to $115.6 million, or $1.21 per share on an adjusted basis, above the $1.13 per share estimate. So, why is the stock down? 

Person working on a part in a CAD program.

Image source: Getty Images.

Management said that it expects third-quarter revenue to be $1.11 billion to $1.13 billion and earnings to be between $1.22 and $1.28 per share. Revenue was in line with analyst estimates of $1.12 billion, but earnings guidance fell short of the $1.30 expectation. 

Now what

Investors often use estimates to gauge the future earnings growth of a company, and in this case they had priced in more growth that Autodesk is expecting to deliver next quarter. That's not necessarily bad long term, but it can sink a stock a day after earnings or guidance is announced, especially if results are weaker than expected for growing tech stocks

Autodesk still has an extremely strong moat in its business, and that's not changing because of one weak guidance announcement. So, for long-term investors this looks like a great buying opportunity, even if the market's sentiment is against Autodesk today.