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 wireless service providers MetroPCS (NYSE: PCS) and Leap Wireless (Nasdaq: LEAP) were ringing up big gains today, with both stocks up more than 20% at one point, as takeover rumors hit the newswires.

So what: According to Bloomberg, Deutsche Telekom may be prowling the deal circuit again with its T-Mobile USA unit following its ill-fated proposed tie-up with AT&T (NYSE: T). In an effort to gain size and clout in the cutthroat wireless services industry, the company may be interested in merging the T-Mobile unit with the smaller MetroPCS. Based on Bloomberg's coverage, Deutsche Telekom still seems to be keeping many options open, including looking at combinations with other carriers like Leap Wireless and Sprint Nextel (NYSE: S), selling T-Mobile USA outright, or offering the unit to investors in an initial public offering.

Now what: Should Deutsche Telekom come through with an offer for MetroPCS, it would have to provide a premium price to entice investors to sell -- and that is exactly what buyers today are counting on as they excitedly push shares up. But buying on takeover rumors is a tough game that can easily lead to heartbreak if no deal ever materializes. This Fool's view is that speculation like this should be left to gamblers.

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