Yale’s 21.9 percent endowment return in fiscal year 2011 not only bested most of its Ivy League peers, but is also on track to top the national average.

Colleges and universities nationwide returned an average of 19.8 percent on their investments in the fiscal year that ended June 30, according to a preliminary study of 284 institutions released Monday by the National Association of College and University Business Offices (NACUBO) and the Commonfund Institute, a nonprofit consulting firm. Yale’s 8.9 percent return lagged behind the national average of 11.9 percent in fiscal year 2010, but the University’s performance surpassed this year’s average.

The University’s non-traditional investment strategy, pioneered by Chief of the Investment Office David Swensen, focuses on illiquid assets such as gas, oil, timber and real estate, but also makes use of long-term assets more readily converted to cash. University President Richard Levin said in a Monday email that Yale’s improved endowment performance with respect to the national average can be attributed to a more typical year for markets. Yale’s endowment “underperformed” in fiscal year 2010, Levin said, because illiquid assets such as private equity and real estate did not keep up with public markets.

The strategy has been emulated by many of Yale’s peer institutions and led the University to gains of nearly 20 percent or more between 2004 and 2007, but hindered the immediate recovery of Yale’s finances in the wake of the recession.

William Jarvis ’77, managing director of the Wilton, Conn.-based Commonfund Institute, said rising domestic equity markets have buoyed endowments invested largely in traditional assets such as United States stocks and bonds over the past few years. Institutions that rely more heavily on diversified illiquid assets, such as Yale, have recently begun to experience strong growth as well and tend to perform better in the long run, he added.

“The more diversified portfolios are beginning now to reassert their performance,” Jarvis said. “But at the same time more traditional portfolios are doing well because the domestic stock market is going up.”

Despite improvement seen across the board in higher education investments, Provost Peter Salovey and endowment experts cautioned that volatility in today’s markets means the strong one-year figures are not necessarily indicative of total financial recovery.

The NACUBO-Commonfund report warned that higher education investment funds have not yet “recovered” from the effects of the recession that hit in 2008. Jarvis said that most college and university endowments have not returned to their pre-recession levels, even with two years of positive returns, as annual endowment spending of roughly 5 percent has partly offset growth at most institutions. For its part, Yale’s endowment, which was valued at $19.4 billion as of June 30, is still below the high-water mark of roughly $23 billion it reached during fiscal year 2008.

Sandy Baum, chairwoman of the economics department at Skidmore College and a senior policy analyst for the College Board, also cautioned that investments are susceptible to the unpredictable rise and fall of markets ­— making careful budgeting always necessary.

Salovey said in a Monday email that significant volatility exists in markets today, particularly in light of the current political tensions in Europe. Administrators continue to budget “cautiously,” he added, and are aware that endowment performances could take a turn for the worse at any time.

While Salovey said the endowment’s one-year returns are less important than its long-term performance, he praised Yale’s investments team for carrying out a strategy that has led to returns above the national average.

“The Yale endowment performance was above this average because of the Investment Office’s talent in both asset allocation — determining the mix of asset classes — and in selecting outside managers with whom to invest,” Salovey said.

After smaller endowments posted greater returns than larger ones two years ago — an atypical occurrence — patterns returned to normal in fiscal year 2010, with larger endowments reporting greater growth. But this year, returns by endowments valued between $51 million and $100 million narrowly topped the 20.2 percent returns seen by the largest class of endowments worth more than $1 billion.

According to Yale’s 2010-’11 financial report, U.S. stocks, bonds and cash made up about one-tenth of the school’s endowment investments at the end of fiscal year 2011, but accounted for more than half the portfolio in 1991.