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: After booking a tidy 4% gain yesterday, shares of mobile telephony IP shop InterDigital (Nasdaq: IDCC) are moving even higher this morning, up as much as 10% at one point.

So what: Yesterday, InterDigital's board announced that it's definitely interested in selling the company "in whole or in part."

Now what: That "in part" part is key. Rumor has it, you see, that interested buyers were bidding as low as $1 billion and $2 billion for InterDigital -- numbers that spooked investors hoping to see something more along the lines of the $4.5 billion that a consortium including Microsoft (Nasdaq: MSFT), Research In Motion (Nasdaq: RIMM), Apple (Nasdaq: AAPL), and EMC (NYSE: EMC) paid for Nortel's patent portfolio earlier this year, or the $14 billion that Google (Nasdaq: GOOG) shelled out for Motorola Mobility (NYSE: MMI). This fear sparked a sell-off in InterDigital stock on Monday.

Turns out, however, that the $1 billion bids were actually for just a part of InterDigital -- meaning the whole of the company could still be worth something in the neighborhood of a Nortel (or a Motorola?). And this confirmation, Fools, is why InterDigital is going right back up again.

What price will InterDigital ultimately fetch? Will it find a buyer at all? Add the stock to your Fool Watchlist and find out.

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.