From the Wikipedia article on acronyms: SAT(s): ([sæt] or ess-ay-tee) (previously) Scholastic Achievement (or Aptitude) Test(s) (US) or Standard Assessment Test(s) (UK), now claimed not to stand for anything.[14]

In other words, just know the acronym and not what the letters stand for?

That seems to be happening with organization names, too. They seem to want to be called by their initials, and don't publicize what they stand for.

We have what some schools unofficially call SATs over here. They are taken at around age 10-11 in English, maths and science. Their actual name is 'National Curriculum Level 2 tests'. Officials discourage the use of SATs as a name and I think there was some copyright complaint from the USA over it.