SAT Subject Tests are run by non-profit Collegeboard. (Creative Commons)

According to the UC website:

Beginning with students applying for the fall 2012 term, SAT Subject Tests no longer will be required and students who do not submit subject test scores will not be penalized during the review process. Some majors at some campuses, however, recommend particular tests, and applicants may submit subject test scores for consideration during the comprehensive review process much the way they do now with Advanced Placement and International Baccalaureate scores.
 
The new rules have caused confusion and anxiety among students who do not know whether they should take SAT subject tests, according to the L.A. Times. Particularily confusing to students: certain programs within the UC system require certain tests, making the application process all the more complex.

Run by the non-profit Collegeboard, The SAT Subject Tests (or SAT IIs) are standardized tests that center around individual subjects, such as chemistry or U.S. History. Some schools require two subject tests.

From one UC student, there is positive aspect to the admission changes.

"I think it will increase the number of applications to the UC system and is a great thing," said Nanxi Liu, a student at UC Berkeley. "The more applicants that can apply the better. SAT tests cost money so this will help more people be able to apply which is good. It will encourage people to who didn't want to pay for the tests to apply. Lowering the requirements is a good thing because there will be more variety in who applies."

Last year, a third of the students who took the subject tests were from California.

Reach reporter Cliff Liu here.