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 Valassis Communications (UNKNOWN:VCI.DL) shot up as much as 23% and finished up 22% on news that it would be acquired by Harland Clark.

So what: The direct-mail and coupon specialist will be taken private be Harland Clark for $1.31 billion or $34.04 a share. Valassis closed at $34.60, which sometimes indicates that shareholders expect a higher bid to come up, but both boards of directors already approved the sale as Valassis's board said after evaluation a range of opportunities, the offer was "in the best interest of Valassis and our stockholders." The deal is expected to close at the beginning of next year, after Valassis pays out its final dividend on January 15.

Now what: This one is pretty straightforward. With the deal approved by both boards of directors, there's no reason to believe the deal won't go through despite several lawsuits from class action firms alleging that the deal is not in the best interests of the Valassis shareholders. Considering shares reached a three-year high on the news, investors seem unlikely to complain.