Aurora, Ill.-based Old Second Bancorp Inc.'s stock was up 8.37% to $13.92 as of 11:18 a.m. ET, following the announcement that it will buy Greater Chicago Financial Corp. for $41.1 million in cash.

The buyer projects 30% in annual cost savings from the transaction, with tangible book value dilution earned back in two years.

Meanwhile, the SNL U.S. Bank Index had slid 0.10% to 620.81. The SNL U.S. Thrift Index, however, was up 0.16% to 946.99. Broader markets were trending upward, with the Dow Jones Industrial Average Index rising 0.13% to 24,778.44, the S&P 500 up by 0.18% to 2,685.34 and the Nasdaq Composite Index rising 0.23% to 6,951.87.

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