Harvey Mudd and CalTech grabbed 2020 admissions headlines for dropping their testing requirement for the SAT Subject Tests. As of February 2020, MIT remains the ONLY school to require SAT Subject Tests of all of its applicants. Insiders believe that MIT may reconsider its Subject Test requirement.
Institutional decisions to make Subject Tests optional may be partially to do with the desire to increase applications. Subject Tests and specifically the SAT Math 2 Subject Test are excellent ways for high achieving students to demonstrate their proficiency.
Students should keep in mind that these super selective STEM schools are not test-optional. Applicants still need to submit an SAT or ACT for admission.