s & p 500 component industry utilities founded 1997 headquarters st. louis missouri u.s. key people warner baxter chairman ceo & president ; greg nelson senior vp and general counsel 1 products electricity 16 900 megawatts and natural gas 2 revenue us 7.531 billion fy 2011 3 operating income us 1.241 billion fy 2011 3 net income us 519 million fy 2011 3 total assets us 23.645 billion fy 2011 3 total equity us 7.919 billion fy 2011 3 number of employees 9 323 dec 2011 3 website www.ameren.com ameren technician replacing a street light . ameren corporation was an american power company created december 31 1997 by the merger of missouri s union electric company formerly nyse uep and the neighboring central illinois public service company cipsco inc. holding formerly nyse cip . 4 it is now a holding company for several power companies and energy companies . the company is based in st. louis missouri serving 2.4 million electric and 900 000 natural gas customers across 64 000 square miles 5 ameren is the holding company for the following 6 ameren missouri ameren illinois ameren transmission company the ameren missouri subsidiary owns bagnell dam on the osage river which forms the lake of the ozarks . ameren missouri is responsible for managing water levels on the lake according to federal regulations . contents 1 history 1.1 origins 1.2 ameren history 2 taum sauk pumped storage plant 3 environmental issues 4 former manufactured gas plant 5 references 6 external links 6.1 taum sauk history edit origins edit prior to the formation of ameren the first major development in the history of its constituent parts occurred in 1929 when the bagnell dam was completed on the osage river and generated almost 175 megawatts of hydroelectricity for missouri s union electric company . the dam also created the lake of the ozarks with 1 400 miles 2 300 km of shoreline . 7 in 1931 union electric light and power sought additional generating sources interurbans being one need and the company began buying power from the keokuk ia dam 150 miles 240 km north of st. louis . union electric later bought the dam providing 134 megawatts of hydroelectricity carried over a longer distance than had ever been achieved before . by the 1950s union electric owned gas operations in and around alton illinois and acquired other utilities to become the third largest distributor of natural gas in missouri . 7 in 1952 ameren s second major constituent the central illinois public service company became a major pooled energy power distributor with its future ameren mate union electric company . the arrangement formed the midwest power pool system . the cips meredosia illinois power station became a key contributor to the pool which also included the later ameren subsidiary illinois power company . 7 in 1963 union electric completed construction of one of the largest pumped storage plants at that time the then 350 megawatt taum sauk plant in reynolds county missouri . 7 in 1984 union electric added nuclear energy to the mix when the callaway nuclear generating station began providing 1 143 megawatts of power from callaway county missouri . 7 ameren history edit 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 . 4 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 . 8 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 . 8 the merger was completed on december 31 1997 when the two public companies became one as ameren corporation which then began to trade publicly on the new york stock exchange with the ticker symbol aee . 4 the former cipsco inc. utility central illinois public services company is now a subsidiary of the ameren corporation holding company known as amerencips . 4 following the merger union electric began doing business as amerenue now known as ameren missouri . today with nine power plants ameren missouri serves 1.2 million power customers and 110 000 gas customers primarily in missouri where more than half of its customers reside in the st. louis metropolitan area . it also serves adjoining parts of illinois and formerly served iowa as well through the mid 1990s . in 2000 ameren formed the holding company amerenenergy resources . 9 it contained two further subsidiaries amerenenergy marketing and amerenenergy generating . 10 in 2002 ameren corporation announced a voluntary retirement program which was offered to approximately 1 000 of ameren s 7 400 current employees expecting to realize significant long term savings . 11 in 2003 ameren acquired the central illinois light company . that utility s holding company cilcorp inc. 12 had traded on the nyse with ticker symbol cer and by the mid 1990s had become a member of the s & p small cap 600 index . cilcorp had been another pioneer utility in the region which had paid a dividend since 1921 . by 1996 it had grown to over us 150 million in assets and carried us 330 million in long term debt . 8 following the 2003 ameren acquisition that utility then became the subsidiary amerencilco . 12 at the end of 2003 ameren s chairman and chief executive charles mueller retired and was succeeded in both positions by gary rainwater the company s president and chief operating officer the past two years . 13 in 2004 ameren acquired from dynegy inc. its third partner from the 1952 midwest power pool system illinois power company . 14 that utility had traded publicly on the nyse under the ticker symbol ipc through the 1980s and paid dividends since 1947 . as of the late 1980s the company generated electricity and natural gas almost entirely from coal plants with less than 1 % fueled from oil and gas . by then with about 360 million in assets it carried long term debt of over us 2 billion . 15 in 1991 illinois power became the subsidiary of holding company illinova corp. which traded on the nyse with ticker symbol iln . illinova had grown to an s & p midcap 400 stock by 1996 with over us 415 million in assets and had brought the ip utility s debt down to us 1.8 billion by then . 8 in a merger completed february 1 2000 illinova corp. became a wholly owned subsidiary of dynegy inc. nyse dyn in which chevron corporation also took a 28 % stake . dynegy in turn had been created in june 1998 from the merger of chevron s natural gas and natural gas liquids businesses with dynegy s predecessor ngc corp. former ticker ngl . ngc had been an integrated natural gas services company around since 1994 . 16 following the 2004 ameren acquisition of the ip utility that subsidiary became amerenip . 17 in 2010 all illinois utilities merged to become ameren illinois company . 9 in december 2004 ameren announced that patrick t. stokes the president and chief executive officer of anheuser busch cos. inc. was elected to the ameren board of directors . 18 in 2009 amerenue signed an agreement to purchase 102 megawatts mw of wind power from phase ii of horizon wind energy s pioneer prairie wind farm in iowa . that s enough to power 26 000 households . the power amerenue is purchasing will tie into the midwest independent system operator miso transmission grid of which the company is a member fulfilling amerenue s commitment to add 100 megawatts of renewable capacity to serve its missouri customers by 2010 . 19 in late 2010 ameren dropped the amerenip amerencips and amerencilco names and became known simply as ameren illinois in 2015 ameren became the first major energy company to open an innovation center at the research park university of illinois at urbana champaign . taum sauk pumped storage plant edit main article taum sauk pumped storage plant a large section of the taum sauk upper reservoir failed draining over a billion gallons of water in less than half an hour . ameren missouri owns the taum sauk pumped storage plant 20 which failed on december 14 2005 causing extensive damage to the east fork of the black river and to johnson s shut ins state park . consequently ferc fined ameren 15 million . the state of missouri has sued ameren for actual and punitive damages alleging ameren recklessly operated the plant and put financial considerations from sale of power to other companies over safety maintenance and engineering . the plant was operated by remote control with no one onsite during pumping operations . rebuilding the upper reservoir of the amerenue taum sauk pumped storage hydroelectric plant cost 450 million and added 635 new jobs to the state s economy while raising state income by 48 million according to a study conducted by the center for economic & business research at southeast missouri state university . the upper reservoir was constructed with roller compacted concrete rcc ; and online in 2010 this 54.5 acre 221 000 m2 reservoir is the largest rcc dam in north america . 21 the 440 megawatt taum sauk pumped storage hydroelectric plant began generating electricity again on april 21 2010 . environmental issues edit ameren missouri sponsors the adopt the shoreline program which enables people to adopt portions of the shoreline for litter control . they also control other shoreline activities in the lake of the ozarks such as the regulation of boat docks seawalls and other structures within the osage project boundary on the lake and downstream from bagnell dam . the company maintains the lake and shoreline protection hotline that anyone who wishes can use to report neglected docks or other concerns they may have about the lake . 22 former manufactured gas plant edit a predecessor of ameren operated a coal gasification plant at the corner of ash and orr streets in columbia missouri which was subsequently demolished . the gasification process contaminated the soil and some groundwater in the area with potentially cancer causing chemicals . ameren has since finished removing contaminated soil as of september 2014 . 23 references edit investor relations board of directors facts about ameren accessdate april 24 2011 a b c d e f ameren form 10 k annual report filing date feb 28 2012 pdf . secdatabase.com . retrieved jan 5 2013 . a b c d ameren form 8 k current report filing date jan 2 1998 . secdatabase.com . retrieved jan 5 2013 . ameren form 8 k current report filing date nov 9 2012 pdf . secdatabase.com . retrieved jan 5 2013 . ameren corporation about us a b c d e ameren corporation 2002 . a century of excellence ameren history 1902 2002 . ameren . a b c d standard & poor s stock guide april 1996 a b ameren form 8 k current report filing date mar 15 2010 pdf . secdatabase.com . retrieved jan 5 2013 . ameren form 10 k annual report filing date mar 30 2000 . secdatabase.com . retrieved jan 5 2013 . ameren corporation announces voluntary retirement program . a b ameren form 8 k current report filing date jan 31 2003 . secdatabase.com . retrieved jan 5 2013 . mueller to retire from ameren ; rainwater to take reins . ameren form 8 k current report filing date mar 24 2004 . secdatabase.com