The University’s Investments Office said Thursday that the Yale endowment earned a 4.5 percent return in the fiscal year ending June 30, outperforming market benchmarks but trailing Harvard in overall performance.

The endowment now stands at $22.9 billion, up from $22.5 billion last year.

While 4.5 percent might not seem like much following years of double-digit gains, including last year’s 28 percent haul, it still is likely to stand as among the highest returns reported by universities nationwide this year, given the sagging economy. The S&P 500, a popular benchmark for the financial markets, fell 13.1 percent in the last fiscal year, and the median return among 165 large institutional funds measured by the Trust Universe Comparison Service decreased 4.4 percent in that period.

Yale’s 4.5 percent return places the University comfortably in the top 5 percent of the funds tracked by the service.

Still, it does not match up to Harvard’s return, which the university announced last week amounted to 8.6 percent. The Harvard endowment now stands at $36.9 billion, the most of any university fund in the country.

The endowment announcements come as observers across the country pay increased attention to the wealth accumulated by many of the country’s leading universities. Some in Congress, led by Sen. Chuck Grassley of Iowa, argue that wealthy universities should spend more of their endowment funds to help reverse the trend of rising tuition and provide more financial aid to families, and have threatened to impose mandatory spending rates.

Yale capitulated to some of Grassley’s demands this year when it announced in January it would increase its spending from its endowment by about 40 percent next year and set a new minimum endowment payout rate of 4.5 percent. With that new policy in effect, spending from the endowment in the 2008-’09 fiscal year will total $1.16 billion, up from $843 million in the fiscal year ending June 30, the University announced Thursday. That spending will comprise approximately 44 percent of Yale’s net revenues.

“The continued growth of the endowment coupled with our prudently adjusted spending policy is providing unprecedented resources for the University in support of its research and educational missions,” University President Richard Levin said in a statement. “Thanks to the exceptional generosity of our alumni and friends and to the extraordinary endowment management by Chief Investment Officer David Swensen and his colleagues, Yale is undertaking ambitious initiatives to strengthen its contribution to the advance of science and to make the superb education it offers more affordable and accessible.”

Thursday’s announcement by the Investments Office was not much of a surprise. As the News reported Monday, a letter sent by University President Richard Levin to donors last week said the Yale endowment had increased to nearly $23 billion in the fiscal year. An unnamed University official confirmed over the weekend that while the Yale endowment did post a positive return in the year ending June 30, that return paled in comparison to what Harvard announced last week.