(Updates trading, adds Cetip spokeswoman comment)
By Tatiana Bautzer and Guillermo Parra-Bernal
SAO PAULO, Feb 26 (Reuters) - The biggest shareholders in Cetip SA Mercados Organizados are willing to accept most terms of an unsolicited takeover offer by rival BM&FBovespa SA, three sources familiar with the matter said on Friday, a major step toward creating the sole exchange and clearinghouse player in Brazil.
According to the sources, who requested anonymity as deliberations on the matter are private, some Cetip board members want BM&FBovespa to limit the scope of due diligence work. BM&FBovespa's offer, unveiled last week, values Cetip at 10.8 billion reais ($2.7 billion).
While the board feels "comfortable" with the 41 real a share that BM&FBovespa presented, some members would like to see the bid slightly improved, one source said.
One way to achieve this would be to allow Cetip shareholders to earn interest pegged to Brazil's benchmark interbank rate on the price-per-share offered from an earlier date, until the deal is concluded, the source said.
The sources said Cetip plans to deliver an answer to BM&FBovespa, the world's 10th largest bourse by market capitalization, as early as next week. The company releases fourth-quarter results on March 3.
A Cetip spokeswoman said in an emailed statement that the board would analyze the proposal, but did not comment on the timing of its decision.
If successful, a takeover would make BM&FBovespa the dominant exchange in Brazil, by controlling depositary and clearing activities for all types of financial assets and sourcing investors with proprietary market data.
Cetip is Latin America's largest securities clearinghouse with a vast over-the-counter, fixed-income derivatives operation.
BM&FBovespa had presented a non-binding offer of 39 reais a share in November, which Cetip rejected, saying it did not fairly reflect the value of the company's operations.
The first source said the offer was shunned rapidly because its non-binding nature threatened to destabilize management's relations with staff.
The negotiations came after years of speculation that BM&FBovespa could pursue an unsolicited takeover of Cetip to grow in registration and custody of fixed-income and credit market instruments, segments in which the bourse has failed to gain market share.
Shares of Cetip were up 1.25 percent in morning trading Friday, and BM&FBovespa gained 1 percent.
BM&FBovespa added over 6 percent as chances grew that the improved offer would succeed.
$1 = 3.9545 Brazilian reais Editing by Lisa Shumaker and Bernadette Baum