Shares in TP ICAP PLC (TCAP.LN) fell in early trade on Tuesday after the company said that 2017 pretax profit declined.
The interdealer broker made a profit of 72 million pounds ($99.9 million) compared with GBP167 million the previous year.
Results for 2016 were restated on a pro forma basis to include earnings from ICAP PLC before the company's merger with Tullet Prebon PLC.
Underlying pre-tax profit, before costs and exceptional items, rose by GBP1 million to GBP233 million.
Revenue increased to GBP1.76 billion from GBP1.69 billion on a pro forma basis.
FTSE 250-listed TP ICAP maintained the final dividend at 11.25 pence a share, keeping the full year dividend at 16.85 pence.
Chief Executive John Phizackerley said the integration of the merger is progressing and the company achieved GBP27 million synergy savings in 2017 ahead of its initial GBP10 million target. He said the company has experienced an encouraging start to 2018, with a pick-up in volatility and interest rates.
At 0830 GMT, shares were down 30.80 pence, or 5.7%, at 507.20 pence.