Fewer applicants are reporting race and ethnicity on college applications following the Supreme Court’s 2023 rejection of affirmative action, according to Class Action’s “Known Unknowns” analysis. The report finds non-reporting increased to 4% from 3.3% across institutions, with the sharpest jumps at Ivy Plus schools (3.2% in 2023 to 5.8% in 2024) and HBCUs (3.2% to 4.9%). The shift complicates oversight and accountability efforts, because fewer students provide the demographic data commonly used to assess enrollment practices. Class Action argues colleges should clearly communicate the value and the perceived lack of risk in sharing demographic information as the admissions environment becomes harder to interpret. The change also extends a longer pattern: over the past decade, the share of students not reporting race on the SAT/ACT nearly doubled, reinforcing concerns that admissions-related comparisons will become less precise and harder to verify without improved institutional data handling.