Fenner's shares fell as much as 10 percent in early trading, making the stock the top percentage loser on the FTSE 250 mid-cap index <.FTMC>.

Fenner, which generates about 65 percent of its group sales in U.S. and Australian dollars, said if results for the year ended August were adjusted for the pound as at December 31, underlying operating profit would have been lower about 9 million pounds.

The pound has gained 6.5 percent against the dollar in the last six months.

The company said visibility in its other business, which makes industrial conveyor belts and accounts for 70 percent of total revenue, was more limited than usual due to lower demand in winter from coal miners.

"U.S. coal volumes are edging upwards but prices remain low and the asset trades between customers have disrupted Fenner's order intake a little, affecting its firm backlog in (Engineered Conveyor Solutions business)," Investec analyst said in a note to clients.

Liberum cut its rating on the stock to "hold" from "buy", citing limited visibility in its conveyor business, order delays in the polymer business and a higher-than-anticipated 10 percent impact from a stronger pound.

The Hessle-based company's stock was down 4.2 percent at 435.8 pence at 1019 GMT.

(Reporting by Aashika Jain in Bangalore)