Kaplan will put you to the test. Graham Holdings' largest subsidiary is perhaps best known for its test-preparation publications, which help students prepare for college and graduate school entrance exams, including the SAT, GRE, LSAT, and MCAT. Kaplan offers prep courses at some 400 locations in 30 countries. Its focus on higher education, though, accounts for more than half of its revenues. Primarily through Kaplan University, the company provides students with online undergraduate, graduate, and professional (including law) degrees in the US and abroad. As part of its business, Kaplan also offers professional development for the financial services, real estate, IT, and other sectors.