Yale University will celebrate the largest class gift in its history this week when it credits the class of '54 with a contribution of more than $110 million.

The bulk of the gift, $90 million, comes from an unusual fund-raising exercise born 25 years ago out of $75,000 in seed money and frustration with the university's financial management.

''Savvy money management is taken for granted by most graduates of universities today, but it is a relatively new phenomenon,'' said Richard Gilder, a member of the class of '54. ''Yale does a great job of managing the endowment now, but back then its investment performance was pretty lousy.''

In 1979, Mr. Gilder and a group of his classmates were attending their 25th reunion and bemoaning the sorry state of Yale's finances, when Mr. Gilder proposed a novel idea: What if they pooled their donations and entrusted them to a professional money manager with a plan to turn the principal and the interest earned over to Yale at their 50th reunion?