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 payments provider ACI Worldwide (Nasdaq: ACIW) fell as much as 12% in early trading before closing down 8%. Investors didn't take well to the company's once more raising its offer to purchase S1 (Nasdaq: SONE).

So what: The deal ends a multi-month drama through which ACI's management has dueled with Fundtech (Nasdaq: FNDT) in bidding for S1. Private -equity firm GTCR has since agreed to acquire the Israeli wealth manager for $352.7 million.

Now what: Cash won the day. ACI management agreed to up the cash portion of its bid after the stock declined more than 20% following the company's first offer. Investors would apparently prefer to keep what little moola ACI has available for other opportunities. Do you agree? Would you buy shares of ACI Worldwide at current prices? Please weigh in using the comments box below.

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