Ace Ltd. said today that board members Walter Scott and Dominic Frederico won't seek re-election when their current terms end in May.

Scott had been chief executive officer from 1989 to 1994, and oversaw the company's 1993 initial public offering, Ace said in a statement distributed today by Business Wire.

Frederico, a former vice chairman of Ace, left to become CEO of Assured Guaranty Ltd., the bond-insurance business it spun off last year.

Ace shares fell 52 cents, or 1.2 percent, to $44.46 in New York Stock Exchange composite trading. The shares have fallen 0.3 percent in the past 12 months, compared with a 2 percent decline in the Standard & Poor's 500 Insurance Index.