Taipei, Taiwan, R.O.C. - December 30, 2005 - United Microelectronics Corporation (TAIEX: 2303, NYSE: UMC) absolutely refutes the claims made by the United Daily News that its Vice Chairman Peter Chang sold shares of UMC between September 28 and October 5 of 2005. These claims are completely false. To clarify, Vice Chairman Chang applied to sell 3 million shares of UMC shares on August 16, 2005 in full compliance with reporting procedures for management of listed companies. The purpose of the sale was for the repayment of a house loan and for tax payment purposes. He completed the sale of these shares between August 22 and September 15 of 2005. Furthermore, he made no subsequent share sales after September 15. There is absolutely no evidence to suggest insider trading by any Peter Chang or any other UMC executive.