Tullett, which has agreed to buy ICAP Plc's hybrid voice broking business, reported an 11 percent rise in underlying operating profit to 67 million pounds for the first half ended June 30.

Revenue rose 4 percent to 430.3 million pounds, boosted by Americas and Asia Pacific.

Over 60 percent of revenue in the period was earned in U.S. dollars, while euros accounted for 10 percent of the total figure, Tullett said.

After the referendum, sterling fell to its lowest level against the U.S. dollar since 1985.

"The UK and the EU are now entering uncharted waters. We are following political events very closely, but any decisions that we have to make will be based on facts and not speculation," the company said in a statement.

Tullett said its $1.5 billion deal with ICAP was expected to complete during the latter part of the year, with costs related to the deal amounting to 13 million pounds in the first half.

Tullett said it expected total costs for the deal to be 37 million pounds in the full year.

Shares in the company were up 0.18 percent at 326.4 pence at 0706 GMT on the London Stock Exchange.

(Reporting by Noor Zainab Hussain in Bengalurul Editing by Sunil Nair)

Stocks treated in this article : Tullett Prebon Plc, ICAP plc