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 senior-housing operator Nationwide Health Properties (NYSE: NHP) climbed as much as 13% in early Monday trading after larger competitor Ventas (NYSE: VTR) said it would purchase the company for about $45 per share.

So what: The all-stock deal values Nationwide at about $5.8 billion and represents a 15% premium to Friday's closing price. The combined company will become the market's largest health-care real estate investment trust, operating about 1,300 assets across the U.S. and parts of Canada.

Now what: The offer seems like a reasonable one for Nationwide. In addition to the decent premium, the proposal gives Nationwide shareholders a chance to benefit from, as CEO Douglas Pasquale put it, "expanded strength, diversification and capabilities." For those who would rather cash out, rivals like HCP (NYSE: HCP) and Healthcare Realty Trust (NYSE: HR), both of which now sport lower forward P/Es than Nationwide, might be cheaper baby-boomer bets going forward.

Interested in more info on Nationwide? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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