For Brown University, posting the best investment return in the Ivy League added more than $2 billion to its endowment. It also thrust the school into an elite club: It reached the threshold for paying a federal tax on investment income.

Other schools expected to pay the tax include the University of Chicago, Vassar College, Wesleyan University, Denison University, Colby College, Davidson College and Harvey Mudd College, according to data released Friday by the National Association of College and University Business Officers and TIAA.

Colleges endowments booked average returns of 31% for the year ended June 30, the data show, putting more of them in line to pay a controversial levy that schools have been lobbying against since it became law in 2017. Private schools with at least 500 students and $500,000 in endowment assets per pupil must fork over 1.4% of their net investment returns.

“We’re going to see more private colleges pay the tax because endowment values grow over time,” Liz Clark, vice president for policy and research at NACUBO, said in an interview.

Representatives for most of the schools confirmed they met the threshold, except for the the University of Chicago, which said it hasn’t finalized its financial evaluation. The few dozen colleges that were already paying the tax include the richest: Harvard, Yale, Princeton and Stanford universities.

Brown’s endowment returned 51.5% in the last fiscal year, boosting the fund’s value to $6.9 billion, or about $796,000 per student, the school said. It had ended the previous 12-month period below the $500,000 threshold.

Despite their strong performance recently, endowment managers expressed growing concern about rising inflation, according to the report, which encompasses 720 institutions with a combined $821 billion of endowment assets.

The average spending rate by endowments -– to fund scholarships, professor salaries and other expenses -- was virtually unchanged from the year prior at 4.5%. Endowment revenue was likely a larger part of 2021 operating budgets because tuition and auxiliary revenue at many institutions was down because of the pandemic, the study said.

This article was provided by Bloomberg News.