* Cetip's profit at 80.1 mln reais beats poll estimate
* BM&FBovespa profit jumps in spite of revenue decline
* Results highlight resilience amid difficult markets
SAO PAULO, May 9 (Reuters) - Exchange and clearinghouse companies in Brazil posted mixed first-quarter results on Thursday as their efforts to contain expenses helped reverse the effects of shaky equity, debt and credit markets.
Companies in the so-called market structure industry saw weak trading and registration volumes in some segments, sharpened their focus on efficiency, and fought to keep pricing stable in the quarter. Expense reductions were for the fifth straight quarter the defining element behind profits.
Profit at BM&FBovespa SA, the nation's sole listed bourse, rose 22.9 percent in the quarter after two straight drops, while net income at clearinghouse Cetip SA Mercados Organizados rose 3.5 percent thanks to a surprising increase in revenue at its financing unit and stable expenses.
BM&FBovespa booked net income of 267 million reais ($133 million), compared with the 278 million reais estimated by five analysts in a Thomson Reuters poll. Compared with a year earlier, profit slipped 4.8 percent.
In the case of Cetip, profit came in at 80.1 million reais, above the 72.2 million reais expected by on average by six analysts polled by Thomson Reuters. Compared with the same quarter a year earlier, profit climbed 12 percent.
The performance of BM&FBovespa and Cetip highlight the reality of Brazilian financial markets, which are grappling with dwindling confidence, rising inflation and low growth despite interest rates nearing record lows. Brazil's Bovespa stock index is the worst performer among major markets this year.
According to Francisco Carlos Gomes, acting chief executive of Cetip, the earnings beat "demonstrated our ability to perform well even in the midst of tough market conditions ... we proved our resilience."
BM&FBovespa handles all of the country's equities and derivatives trading and is the main beneficiary of stock listing activity. Cetip books 97 percent of local bond deals and sells liens on car loans - a gauge of how well domestic credit markets are performing.