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 Silgan Holdings (Nasdaq: SLGN) surged as much as 17% in early trading and remain up nearly that much as investors cheered its plan to spend $4.1 billion to acquire plastic container maker Graham Packaging (NYSE: GRM).

So what: The deal isn't without risk. With $916 million in debt versus $175 million in cash on its balance sheet, Silgan will solicit as much as $4 billion in outside financing to complete the transaction.

Now what: As Foolish colleague Brian Pacampara points out here, there's probably enough operating leverage in this deal for investors to give Silgan a look.

The price may also be right. Even with today's pop, the stock now trades near its three-year-high multiple to normalized earnings (19.71), reached on July 17, 2007. Shares of Silgan are up more than 43% since. Expect the rally to continue for a while.

Interested in more information on the companies mentioned here? Add Silgan Holdings and Graham Packaging to your watchlist.