(NYSE: EXC) on Thursday raised its all-stock takeover bid for NRG Energy (NYSE: NRG) by 12.4% to around $7.45 billion, saying it has identified another $1.5 billion in savings from a potential deal. The group said it is now offering 0.545 of its own shares for every NRG share, up from a previous exchange rate of 0.485 shares. The new offer is worth around $28.10 a share, or $7.45 billion, based on Exelon's closing price on Wednesday. Exelon Corp. plunged $2.19 or 4.25% to $49.37. NRG Energy Inc. (NYSE: NRG) fell $1.25 or 4.80% to $24.80. Drugstore chain Walgreen Co. (NYSE: WAG) announced on Wednesday that its same store sales jumped 3.4% in June. Shares of the company finished at 64 cents or 2.18% to $28.70. Semiconductor maker Xilinx Inc. (NASDAQ: XLNX) said Thursday that it now expects June-quarter sales to decrease about 5% sequentially, compared to previous forecast of down 4% to up 4%. Illumina Inc. (NASDAQ: ILMN) said late Wednesday that its second-quarter revenue will likely fall below prior forecast because of a slowdown in the number of genetic studies and lower foundation funding. Illumina said it expects to report revenue of $161 million during the quarter, based on a preliminary assessment. It previously projected revenue between $168 million and $173 million. Shares of the company sank $4.68 or 12.27% to $33.46. The European Central Bank left its key lending rate unchanged at a record low of 1% following the monthly meeting of the bank's rate-setting Governing Council.  European stocks settled with losses. The UK FTSE declined 106.44 points or 2.45% to 4,234.27. The German DAX and French CAC decreased 3.81% and 3.13% respectively. Asian stocks finished lower. The Nikkei 225 fell 18.51 points or 0.19% to end at 9,939.93. The Hang Seng index of Hong Kong dropped 1478 points or 0.81% to 18,378.73. NYMEX crude oil for August delivery declined d $2.58 or 3.27% to settle at $66.73 a barrel.