Colleges can gather plenty of information about a candidate’s potential financial status just from the application. Parents’ job, education levels, number of siblings, their year in school (including college) and their institution, applicant’s zip code and high school, EC’s etc. are all factors that can be analyzed to predict degree of need from your admit pools, regardless of their admission plan. And then, of course, there is the historical data as well, including what was actually handed out (by school/zip code/number of siblings, etc.). My guess is that both the admissions and financial aid offices are crunching a lot of numbers to keep fully aware of how the admit pool might impact funds available for financial aid. This doesn’t mean that they are violating “need-blind” policies during the admissions process or that they don’t have an effective information barrier between the two offices.
(Matching programs such as QB and targeted outreach efforts are specifically designed to bring in more high-need candidates and the institution will typically have the dedicated funds for those groups. They know how many to admit and how much to give out. At that point, “need-blind” becomes irrelevant but so does making an admission decision by ability to pay)
In recent years UChicago has pivoted to “no barriers” (ie meeting 100% of “full demonstrated need”) so clearly they have to be able to afford that; it requires hitting a magic number of available yearly funds as well as understanding the parameters (best case, expected, worst case) on the draw-down of those funds. As long as they have done the proper analysis to establish those parameters, they can be reasonably confident as to funding availability for this or that class, including those pulled from the waitlist.
It’s too early to speculate on the full impact of the pandemic on university financial aid funds, but I know that year-end 2018 saw some pretty bad market performance as well (our portfolio lost 15%, for instance) and yet both my kids at UChicago received about what we expected for need-based aid. There’s a lot more to a financial aid calculation than what the market is doing that quarter. A long-run recession or depression might be another matter.