The University's endowment grew by about $1.2 billion during the 2003-04 fiscal year, according to a report released in late January by the National Association of College and University Business Officers (NACUBO).
That represents an increase of 13.7 percent for the University — less than Harvard University's 17.5 percent growth and Yale University's 15.5 percent growth.
Princeton's endowment now stands at $9.9 billion. It ranks fourth in the country, preceded only by Harvard ($22.1 billion), Yale ($12.7 billion) and the University of Texas System ($10.3 billion).
"The endowment fluctuates each year because of three key factors — gifts to the University, expenditure which drains money and the University's investments," said Andrew Golden, president of the Princeton University Investment Company (PRINCO).
The most significant of these factors is the University's investments, which yielded a 16.8 percent growth in the past year, he said. PRINCO is responsible for the reinvestment and management of the University's endowment.
The University has done better in the past two years than previously due to a recovering national economy, said treasurer Christopher McCrudden.
The money made available from the increase is put directly into the University's operating budget.
Nevertheless, the budget isn't based on the yearly fluctuations of the endowment. It depends instead on its longterm performance, McCrudden said.
"When viewed over longer time horizons, we've consistently done very well," he said.
The financial aid program, 98 percent of which is funded by the endowment, directly benefits from the growth.
"We have the best financial aid program in the country," McCrudden said. "The rise in endowment means we have more resources in total for the students and faculty."
The increasing endowment does not have a direct effect on students' lives because of a spending rule set forth by the Board of Trustees, McCrudden explained. The endowment is set up like a mutual fund, in which each University program owns a certain number of units. The rule states that the amount of spending per unit of endowment can only increase by 5 percent each year.

More than 40 percent of the University's operating budget is funded by the endowment. This allows for greater flexibility in financial plans, McCrudden said.
"[The University] has some stability . . . because we know with certainty that the money will be available," he said.