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 POZEN (NASDAQ:ARLZ), a pharmaceutical company focused on developing therapies to treat acute and chronic pain, lifted the pains of its shareholders away this morning by rising as much as 29% following the announcement of an overseas acquisition.

So what: Under normal circumstances the acquiring company is not often the one that soars, but there are substantial dollar-saving implications with POZEN's purchase.

According to the press release, which surprisingly came out while the market was open, POZEN announced the acquisition of Tribute Pharmaceutical Canada for what amounts to approximately $146 million. When the transaction is complete, which is expected in the fourth quarter of this year, the new company will be renamed Aralez Pharmaceuticals PLC.

However, what's truly material about this deal is that POZEN will relocate its headquarters overseas to Ireland, thus escaping the markedly higher than average marginal corporate tax rates in the United States. Known as a tax inversion deal, this buyout could save POZEN a substantial sum of money since Ireland's peak marginal tax rate for corporations is a mere 12.5% compared to as much as 40% in the United States.

Now what: While POZEN's management can spin the deal as bolstering their portfolio and international presence, the real allure are the tax savings -- even if they don't want to admit it. As you can tell by the reaction of the stock, the savings could be substantive and would make POZEN's current P/E of 12, even following today's monstrous run higher, look even more attractive.

It's possible POZEN could still offer additional upside to investors, but they should also keep in mind that POZEN's primary products are licensed-out and its drug development pipeline is far from a sure thing. For instance, POZEN has received two complete response letters concerning the manufacturing process for its low-dose aspiring combo of PA8140 and PA32540 last year alone. Beyond its licensed products, POZEN doesn't have much to be proud of in recent months.

For now I'd be comfortable monitoring from the sidelines, but would encourage investors to use its developing drugs as the catalyst of whether or not POZEN is worth buying.

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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