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 equipment rental company RSC Holdings (NYSE: RRR) soared a staggering 55% today after rival United Rentals (NYSE: URI) agreed to acquire it for about $1.9 billion.

So what: The cash-and-stock deal values RSC at $18 per share and represents a whopping 58% premium to its Thursday closing price. United Rentals is making the move to add "less volatile" revenue from industrial customers, and judging from its own 4% stock jump, investors seem quite satisfied with the strategy, as well as the price being paid.   

Now what: While RSC looks all popped out, United Rentals might be a long-term opportunity worth looking into. The transaction -- which should close in the first half of 2012 -- is expected to be accretive to United Rentals in the first full year and bring in more than $200 million of annual cost savings. "This transaction marks a transformative moment in our company's history," United Rentals CEO Michael Kneeland said. "We have a tremendous opportunity to become the supplier of choice for customers throughout North America."

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

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

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.