既にご存知の方々もいらっしゃるかもしれませんが、Northwestern (Kellogg)、Dartmouth(Tuck), Columbia, NYU (Stern)への出願に際してIELTSスコアの使用が可となっています。
◆Northwestern
Test of English as Foreign Language (TOEFL) and International English Language Testing System (IElTS) All candidates who are not U.S. citizens or U.S. permanent residents must send a valid TOEFL or IELTS score to Kellogg. The score results from both tests are valid for two years.
http://www.kellogg.northwestern.edu/programs/full-time-mba/admissions/international-candidates.aspx
◆Tuck
Tuck accepts both the TOEFL® (Test of English as a Foreign Language™), IELTS (International English Language Testing System),
http://www.tuck.dartmouth.edu/admissions/admissions-faq
◆NYU
All applicants whose native language is not English and who have not received a university degree in an English-speaking country must take the IELTS (International English Language Testing System) or the TOEFL (Test of English as a Foreign Language).
http://www.stern.nyu.edu/programs-admissions/full-time-mba/admissions/application-instructions/standardized-tests
◆Columbia
International students who do not have a bachelor’s, master’s, or doctoral degree from an institution in which all instruction is conducted in English must take either the TOEFL (Test of English as a Foreign Language), the PTE (Pearson Test of English), or the IELTS (International English Language Testing System).
https://www8.gsb.columbia.edu/programs-admissions/mba/admissions/application-requirements#4