After all the admission tests, campus tours and college applications, after nervous weeks of waiting followed by the joy of acceptance or heartache of rejection, many high school seniors aiming for selective schools find one spring date looms large: May 1.

That has long been their primary deadline to choose a college.

Now the coronavirus crisis is leading a growing number of colleges and universities to extend the yes-or-no deadline for admitted students to June 1 or even later. This movement is just one sign of mounting strains on admission and enrollment systems amid the global health emergency and economic shocks that are causing layoffs and ravaging college-savings accounts.

Among more than 100 schools offering a one-month respite from the traditional May 1 decision day are George Mason University in Northern Virginia, Oregon State University and Williams College in Massachusetts.

David Burge, vice president for enrollment management at George Mason, said it was an “obvious” call to give families more time to assess their means and choices as students focus on their learning, safety and well-being. “If there’s something a university can do that would give even a millimeter of help, why wouldn’t we?” he said.

Others plan to stick with the May 1 deadline but help individual students as needs arise. “What’s the next month going to do, other than push everything back further?” asked Charles Deacon, dean of admissions at Georgetown University.

In another development, turmoil in admission testing has raised questions about whether colleges will waive test score requirements for college-bound students who are now high school juniors. This week, the April 4 national session of the ACT was postponed to June 13, and the May 2 administration of the SAT was canceled.

In response, Case Western Reserve University in Ohio said Wednesday it will go “test-optional” on a trial basis for those applying to enter in fall 2021. George Mason is already test-optional, and Oregon State is moving in that direction. But most highly ranked universities are not.

“We would rather students focus as best they can on their academic subjects rather than worrying about the SAT or ACT,” said Richard Bischoff, Case Western Reserve’s vice president for enrollment management. “Testing has always been just one factor in our evaluation of applications, and we are confident that we will continue to make quality admission decisions for those students who are either unable to test or who choose not to submit test scores.”

Across the country, many colleges are also canceling crucial events this spring meant to showcase their campuses to admitted students. Instead they will rely on virtual tours and outreach from faculty, current students and staff to help persuade them to enroll.

Analysts have a dire outlook for higher education. In coming months, “universities face unprecedented enrollment uncertainty, risks to multiple revenue streams, and potential material erosion in their balance sheets,” Moody’s Investors Service wrote in a report Wednesday.

The enrollment upheaval will multiply challenges in higher education that have been brewing for years because of demographic shifts and economic factors. Some states, especially in the Northeast and Midwest, are producing fewer high school graduates, shrinking the pool of potential college applicants. Many colleges also struggle to recruit students from low-to-moderate-income families and those whose parents didn’t go to college.

Those problems will be compounded if disadvantaged students can’t visit the schools that admit them because communities are on a public-health lockdown. “Makes it tough for them to get a real feel for the place,” said an admissions dean at a prestigious university who spoke on the condition of anonymity because he was not authorized to speak publicly.

There are certain to be major enrollment challenges in the next few months for private colleges that were already scrambling to fill seats and meet tuition revenue targets before the novel coronavirus emerged in China. Some had slashed sticker prices in recent years, and others had shrunk or closed.

Those schools and public universities could draw far fewer international students in a moment of deep uncertainty for global travel and public health in the United States. They might also have trouble recruiting students from other regions of the country who now want to stay closer to home.

Jenny Rickard, president and chief executive of the Common Application, a nonprofit portal used by hundreds of colleges, likened the situation to the national trauma after the September 2001 terrorist attacks. Inevitably, she said, crises influence decisions for students who drew up college lists and applied long before hearing about the virus.

“If it’s far away, and if it was the student’s first choice, it might not be anymore because of these circumstances,” Rickard said.

Mindful of that possibility, some selective colleges may take a second look at geography this month as they make admission decisions. One enrollment leader for a competitive university in the Eastern United States, who spoke on the condition of anonymity to describe the process candidly, said a student from a nearby state might get an edge this year over one from the West Coast with equal credentials. “She can drive here with her parents,” this leader said. “Her parents are going to say, ‘You’re a day away, and if the airport’s closed down, we can come and get you.’ ”

Public universities might face a decline in out-of-state students, who pay higher tuition, and higher demand from in-state students whose families are seeking discounts. That is one of numerous emerging scenarios that could threaten the fiscal stability of state flagships and regional universities.

Even when students commit to enroll in the spring, they might change their mind over the summer and forfeit deposits.

With so much uncertainty, predictions of how many admission offers will be accepted and then turn into enrolled and tuition-paying students in the fall — a critical measure known as yield — are becoming very dicey very fast.

“There’s no yield model right now that’s going to be worth a damn,” said Jon Boeckenstedt, vice provost of enrollment management at Oregon State. Boeckenstedt has been leading a campaign for colleges to ease up on deadlines.

He said he believes that events could even push a June 1 decision deadline back to July. The market crash, he said, “has been a sucker punch to parents and students. People who previously might not have thought twice about paying any specific amount are going to think twice or three times. We need to give them more time.”

Williams, a private liberal arts college, is much more selective than public George Mason or Oregon State. But it came to the same conclusion. “We really just wanted to build in a little more breathing room in this extraordinary moment,” said Liz Creighton, dean of admission and financial aid for Williams.

Some contend that maintaining the schedule will help students gain clarity at a time when so much of the world seems up in the air. James G. Nondorf, vice president for enrollment and student advancement at the University of Chicago, said his school will “definitely not” be pushing back the May 1 deadline. “Do we really want to extend the uncertainty of ‘Where am I going to go to college?’ for another month?” he said. “That’s cruel.”

But the university, a private research institution, is in a strong fiscal position. It evaluates applicants on their merits, without considering family income, and it pledges to meet the full financial need of students it admits. The university is not in danger of failing to fill its incoming class.

Among public flagship schools, the University of Utah this week moved its decision day to June 1. But most are holding to their enrollment timetables.

“At this time, there are currently no changes to the May 1 confirmation deadline,” Shannon Gundy, executive director of undergraduate admissions for the University of Maryland, said in a statement.

Gundy said the admissions staff remains “open for assistance and ready to answer questions through email and phone.”

A senior official at the University of North Carolina at Chapel Hill said the school is keenly aware of the stress on college-bound students and wants to help them.

“Right now, we’re planning to stick with May 1,” said Stephen M. Farmer, vice provost for enrollment and undergraduate admissions. “But we understand circumstances can change, and we’re going to keep a close eye on this through early April.”