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What: Shares of Align Technology (NASDAQ:ALGN), a developer of computer-aided design and manufacturing services for the dental and orthodontics industry, plummeted by as much as 13% during Monday's trading session. Its shares had rebounded ever so slightly and were off by roughly 11% as of 3:30 p.m. ET.

So what: The culprit behind the move lower? I'd look no further than the overall weakness in the stock market. As of 3:30 p.m., all three major U.S. indexes were off by 1.4% to 2.2%, putting pressure on most industries. The strain was felt especially fierce among healthcare companies, which is the sector Align Technology calls home. The thinking among more skittish investors could be that, if the market continues to pull back, discretionary spending on its Invisalign systems and other dental devices could fall.

Additionally, Align Technology's first-quarter guidance for fiscal 2016 was a bit lighter than what Wall Street expected. As reported on Jan. 28, Align Technology guided its Q1 EPS to a range of $0.37 to $0.40. However, Wall Street had expected EPS of $0.48 in Q1 2016. A bright spot in its forecast was its call for $232.5 million to $236.6 million in revenue compared to the consensus at the time of just $226.5 million. The concern here is that higher revenue with lower profit may mean potential margin erosion. Today's move lower may simply be more carryover from its Q4 earnings report and Q1 guidance.

Now what: Here's the interesting thing: Align Technology also offered up fundamentally positive news today by announcing that its Invisalign System is now available in India. Having more geographic reach is a good thing that should help diversify its revenue stream over the long term.

Today's trading action is a good reminder not to get too caught up in the day-to-day movements of your portfolio holdings (whether they're up a lot or down). The only new information being released from Align pertains to its expansion into India, and that certainly doesn't appear to change our thesis in a bad way. As long as you feel that the broader thesis is still intact -- namely that consumers are willing to spend more each year to ensure their smile is as beautiful as possible -- then there's little reason to worry about today's drop.

Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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