What happened

3D printer maker 3D Systems (NYSE:DDD) rocked the stock market last week, preannouncing a huge revenue beat for its fiscal fourth quarter and watching its stock price double overnight in response.

After letting the stock coast higher for a few days on that news, investors began taking profits earlier this week -- but now they're back for a second bite at the apple, and 3D Systems shares are skyrocketing again, up 23.5% as of 3 p.m. EST.

Three colorful arrows racing straight up on a black background

Image source: Getty Images.

So what

It's not just 3D Systems shareholders who are having a good day today, either. Shares of rival 3D printer makers Stratasys (NASDAQ:SSYS) and ExOne (NASDAQ:XONE) are up as well, rising 13.2% and 12.3%, respectively. Curiously, though, there doesn't appear to be a clear catalyst for any of these stocks moving higher today.

So what are we seeing here? Is this just momentum traders betting on which stock will become "the next 3D Systems" (and, apparently, guessing that it will be 3D Systems itself)?

Perhaps. There's certainly been enough momentum trading going on in the stock market these past several months for that to be the answer.

Now what

But there also could be another reason. Speaking at the 23rd Annual Needham Virtual Growth Conference yesterday, 3D Systems CEO Jeffrey Graves told investors that the additive manufacturing industry's "growth rates are projected to be very exciting" this year, with research suggesting sales could perhaps grow as much as 24%, according to a transcript prepared by SeekingAlpha.  

3D Systems has already enjoyed a rebound in the third quarter and as its recent preannouncement showed that momentum continued in the fourth quarter, which tends to back up the market research. Granted, it remains to be seen if Stratasys and ExOne will enjoy similar bumps. But because this 24% projection concerns the whole 3D printing industry, and not just 3D Systems, it would seem there really is a reason -- other than just plain momentum -- why 3D printing stocks are going up like fireworks all across the sector today.

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.