LONDON (Bloomberg) - Catlin Group Ltd., owner of the largest insurance unit at Lloyd's of London, said first-half profit rose 77 percent as investment returns more than tripled.

Net income increased to $195.8 million from $110.5 million a year earlier, the Bermuda-based company said on Friday in a statement. Net investment returns jumped to $195 million from $53.9 million a year ago.

"We were assisted by a significant improvement in investment return during the period, which compensated for a higher than usual frequency of large single-risk losses," CEO Stephen Catlin said in the statement.

Catlin raised $290 million in a share sale earlier this year to boost the amount of capital against which it can write policies as premium rates rise in the energy and catastrophe markets. The rights offering helped push down the insurer's share price by 13 percent this year, underperforming Hiscox Ltd. and Amlin plc.

Catlin increased its first-half dividend to 8.2 pence a share from 7.5 pence a year ago.

Lloyd's insurers, including Brit Insurance Holdings plc. and Beazley plc., were last week hurt by foreign exchange losses on premiums yet to be paid as the British pound strengthened against the dollar.