Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Stratasys (NASDAQ:SSYS) fell more than 10% during Wednesday's intraday trading, then pared its losses to close down around 6% after industry peer 3D Systems reported disappointing preliminary earnings and forward guidance.

So what: You read that right: Apart from merely setting the date for its own March 3 quarterly earnings announcement, Stratasys released no significant news today. Instead, it was guilty by association with 3D Systems, shares of which plummeted after the company blamed higher investments in sales, marketing, and R&D for lower-than-expected earnings in both Q4 and full-year 2014.

To be fair, Stratasys did almost the exact same thing three weeks ago, telling investors to expect full-year 2014 non-GAAP net income of $2.15-$2.25 per diluted share, or significantly below average estimates for earnings of $2.33 per share.

Now what: However, also like 3D Systems, Stratasys expects 2014 revenue to come in the range of $660 million-$680 million, which was well above expectations a few weeks ago for 2014 sales around $656.83 million -- and that, of course, is the expected byproduct of both companies' investments as they jockey for the lead in the fast-growing additive manufacturing industry.

Considering nothing has happened today to change Stratasys' long-term story, that's why I still think investors would be wise to hold tight to their shares.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.