The London Stock Exchange Group said on Wednesday that net profit slid 42 percent in its first half.
The exchange said that increased costs offset a jump in revenue.
The company, which operates the London Stock Exchange and Italy's Borsa Italiana market, said in a statement that profit after tax dropped to £67.1 million ($107 million, 79 million euros) in the six months to September 30 compared with the outcome in the equivalent period in 2012.
Revenue increased by 44 percent to £504 million following the company's acquisition of a majority stake in clearing house group LCH.Clearnet, which contributed also to group costs soaring 63 percent to £337.2 million.
"This has been a good overall first half for the Group," chief executive Xavier Rolet said in the statement.
"We remain focused on developing growth opportunities," the Frenchman added.
Rolet has been at the helm of the group for the past four years, during which he has aggressively wooed foreign companies to list in London and has enlarged the business via a string of acquisitions.
Notably last year, he announced a deal to buy a majority stake of up to 60 percent in LCH.Clearnet. However, Rolet failed in 2011 to purchase Canada's TMX Group Inc, operator of the Toronto Stock Exchange.
Clearing houses play a key role in the transaction of shares between two parties, charging clients a fee to guarantee deals should one side default.