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 industrial real estate investment trust ProLogis (NYSE: PLD) climbed as much as 12% as investors reacted to a potential merger between ProLogis and AMB Property Corp. (NYSE: AMB). AMB was up nearly 10% in intraday trading as well.

So what: As The Wall Street Journal pointed out, ProLogis and AMB cater to major global clients such as Nike and Amazon.com by offering them warehousing space in key locations such as Long Beach, Calif., Rotterdam, Netherlands, and Tokyo. If the two were to merge, the combined company would have an even more impressive global footprint. In addition, there's also the standard post-merger cost-cutting that could go on which could see the combined company take a bite out of the expense line.

Now what: The deal is still in the discussion stage, and based on company comments, it's unlikely we'll hear much out of either company until a deal is reached or the discussions fall apart. Since the deal is expected to be executed as a merger of equals, there's no speculative opportunity to bet on a target company here. However, it's a deal worth watching because the $14 billion industrial REIT that could emerge may be a very interesting investment.

Want to keep up to date on ProLogis? Add it to your watchlist.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.