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 construction-materials maker Texas Industries (NYSE: TXI) built up big gains today, having risen by as much as 41% after the company announced the termination of a standstill agreement. The stock fell back a little but still closed with a 9% gain.

So what: Under the agreement, inked in July 2010 with one of the company's largest shareholders, NNS Holding and Nassef Sawiris agreed not to pursue a hostile takeover effort. The agreement was set to expire at the end of the year, so this termination merely accelerated that termination.

Now what: Sawiris holds shares through NNS and has an approximately 20% stake in the company, and the agreement meant he could not acquire more than 20% of Texas Industries common stock or more than 20% of the outstanding debt, among other things. Sawiris is also the CEO of an Egyptian construction company, Orascom Construction Industries, and had amassed his stake last year even as he had previously pushed for three new board members in 2009. Now that the agreement is gone, it's a possibility for Sawiris to acquire more shares and make some changes, which investors are pleased about.

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