“Rather than fight for special treatment, universities should join me in recognizing that young adults are facing a college debt crisis as a result of the uncontrolled escalating costs,” Mr. Reed said in an email. “We should work together to solve this runaway price issue once and for all.”

The tax would affect about 140 colleges and universities, according to a list compiled by The Chronicle of Higher Education.

Universities have been fiercely protective of their endowments, and have ramped up lobbying efforts to keep control over them.

Some argued Friday that the tax plan would put a damper on gifts, because donors would not want to see the impact of their gifts diminished by the tax.

Terry Hartle, senior vice president of the American Council on Education, a trade group, said colleges and universities should be treated differently from foundations. “Private foundations give money away, that’s not the purpose of colleges and universities,” Mr. Hartle said. “If you wanted to treat them the same, you’d apply this to all colleges and universities regardless of the value of their endowments, not just a handful of private ones.”

At Agnes Scott College in Decatur, Ga., which has an endowment of more than $200 million, the president, Elizabeth Kiss, said that most students were minorities and 40 percent had incomes low enough to qualify for federal Pell grants. Because of the endowment, she said, “We are able to give financial aid to basically pretty much all of our students.”

The tax, she said, would amount to a $350,000 cut to an overall budget of $52 million. “This is an institution that had a 1 percent pay raise this year, so it’s not like we’re fat cats,” Ms. Kiss said.