In 1995 shareholders of both CIPSCO Inc. and of its neighboring utility of twice its size, the S&P 500-listed Union Electric Company, approved the merger of the two companies, which were to then be combined as Ameren Corporation. Both of those former utilities had traded publicly on the New York Stock Exchange, under ticker symbol CIP and UEP, respectively. At the time of the merger, Union Electric had assets of nearly US$600 million, but still carried nearly US$1.8 billion in long-term debt, although down from US$2.5 billion which it had accumulated by the 1980s. CIPSCO had assets of about US$210 million, but still carried nearly half of US$1 billion in long-term debt, which it had also accumulated by the 1980s.