The announcement text provided appears to be a corrupted or improperly formatted PDF document, which contains a stream of unreadable binary data and PDF-related metadata. There is no discernible information regarding any specific event, financial report, or company activity that can be summarized for investors or readers. The only identifiable information is the stock code 'C.US' and the company names '花旗集团' and 'Citigroup'.

The announcement text provided appears to be a corrupted or improperly formatted PDF document, which contains a stream of unreadable binary data and PDF-related metadata. There is no discernible information regarding any specific event, financial report, or company activity that can be summarized for investors or readers. The only identifiable information is the stock code 'C.US' and the company names '花旗集团' and 'Citigroup'.