(Recasts to add share performance, background throughout)
SAO PAULO, Sept 9 (Reuters) - Shares in BM&FBovespa SA on Wednesday posted their biggest intraday jump in almost a year after Brazil's sole listed exchange sold part of its stake in partner bourse CME Group Inc to bolster cash.
In a securities filing, BM&FBovespa said the disposal of 3.4 million Class A shares of Chicago-based CME would not alter any of the premises that form the basis of the companies' strategic partnership. At Wednesday's price of $94.33 per CME share, BM&FBovespa may have fetched about $323 million from the sale.
São Paulo-based BM&FBovespa will keep 13.6 million CME shares after the sale and has no plans for further divestments, the filing added.
Speculation over a partial disposal of BM&FBovespa's stake grew in recent months after a run-up in CME's market value and a slump in Brazil's currency drove the value of BM&FBovespa's investment to one-third of its own market value.
BM&FBovespa was up almost 6 percent at 10.85 Brazilian reais a share, its biggest intraday rise since Oct. 11, 2014. The stock is down 22 percent over the past 12 months.
CME shares were down about 1 percent at $93.87 on the New York Stock Exchange.
The divestment came as BM&FBovespa grapples with the toughest environment for local capital markets in a decade.
Efforts by BM&FBovespa Chief Executive Officer Edemir Pinto to buffer the company from the impact of flagging equity listings and trading activity have bolstered earnings, although tax-related disputes and the aftershocks of Brazil's steep recession could have a further negative impact in the future.
BM&FBovespa's board has yet to decide how to use the proceeds from the CME transaction, which generated an estimated profit of 450 million reais ($120 million), the filing added.
$1 = 3.7852 Brazilian reais Reporting by Guillermo Parra-Bernal; Editing by Paul Simao