Insurance giant Beazley's profits fell in the first half due to reduced investment income and the impact of foreign exchange losses.Profit before tax came to $82.3m for the six months to the end of June, down from $82.3m the previous year, despite an increase in gross premiums written to $1.06bn from $1.01bn.Rates rose on average in the portfolio, thanks in part to better than expected economy recovery in the US, the company's largest market.The group posted a combined ratio of 89%, down from last year's 91%.Investment returns fell to $0.3m from $36.1m due to market losses in the firm's fixed income holdings caused by rising interest rates. "Looking forward, however, higher interest rates promise enhanced investment returns," said Chief Executive Officer, Andrew Horton.The company proposed an increase in its dividend to 2.9p from 2.7p.Shares plunged 6.43% to 227.10p at 11:41 on Tuesday.RD