"She is, in some ways the chief administrative and financial officer," said Trustee Chuck Lewis, co-chair of the Capital Campaign. "She's been enormously valuable."
Siegel's departure came as something of a shock to administrators.
"She has really been a very important treasurer, probably as important as any in the country," said President Tom Gerety. "I was really stunned."
Siegel took over as treasurer in February of 1991, succeeding James Scott, who resigned the previous summer.
A number of substantial financial achievements highlight Siegel's tenure as treasurer, including a nearly 50 percent return on the endowment during the last fiscal year, causing the total endowment to rise from $634 million to $912 million in value.
In 1990, before Siegel began, the endowment had only $269 million in assets.
"She is the primary staff person involved in every aspect of running the endowment," said Lewis.
In particular, Lewis said that Siegel was a "very active, highly professional" participant in the investment election process.
Lewis also credited Siegel with providing "a tremendous amount of information" to the Investment Committee, which ultimately makes the decisions about how to invest the endowment.
During Siegel's tenure, the College began the Capital Campaign, which reached its $200 million goal this spring, well in advance of its projected end date.
When the College undergoes major building renovations, there is often a need to borrow substantial sums, which Siegel then manages. Gerety said that Siegel had been successful in borrowing for build at low interest rates.
Lewis added that Siegel has been "very adept at borrowing and managing the liability."
Lewis also said that Siegel had helped to make Amherst's financial situation more solid overall.
"She developed a financial equilibrium policy, which put us on a much sounder financial footing than we were," said Lewis. "She helped to educate the community about fiscal responsibility."
As treasurer, Siegel has extensive responsibilities beyond just financial ones "The job is a broad and far reaching kind of job," said Lewis.
She is also ultimately in charge of physical plant and grounds. As a result, she has been active in working with Director of Facilities Planning and Management James Brassord toward developing a new residential master plan, according to Lewis.
Lewis said that Siegel had been particularly effective in preventing the College from falling behind in the renovation of its buildings and grounds, a trap that many institutions have fallen into. "She has never permitted us to get behind," he said.
Lewis added that Siegel had also made substantial contributions to the College as a member of the priority planning campaign, in preparation for the Capital Campaign.
Siegel's departure means that the College will have to begin the process of searching for a major member of the administration, which Lewis said would likely be a national search.
"These will not be easy shoes to fill," he said.
In the meantime, Gerety said that Associate Treasurer Peter Shea would "undoubtedly be the acting treasurer."
Gerety speculated that Siegel would move into the world of professional financial. "The direction of her interest is to go into investment matters," he said. "She's very marketable."
"She wants to try something else," added Gerety.
Siegel and Shea could not be reached for comment.