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 drugmaker Endo Health Solutions (NASDAQ:ENDP) jumped 29% today after announcing a major acquisition.

So what: Endo Health Solutions is buying specialty drugmaker Paladin Labs for $1.5 billion, and the new company will then be moved into an Irish holding company. Paladin Labs shareholders will get 1.6331 shares of the new company, $1.11, and one share of Knight Therapeutics -- a new company as part of the spinoff. Endo Health Solutions shareholders will get one share of the new company.  

To top it off, adjusted earnings per share for last quarter hit $1.34, and revenue was $715 million -- both down from a year ago but well ahead of expectations.

Now what: Shares of both Endo Health Solutions and Paladin Labs have jumped today, so investors clearly think the combined company is worth more than the companies separately. For investors who owned the stock yesterday, this may be a day to take some gains off the table. It will take time for the merger to go through, and with Endo Health's revenue deteriorating, I don't see another big catalyst until the companies combine and begin generating strong growth, which will take a while.