Meaning of -ACY in English
-acy BrE AmE əs i —Words with this suffix are stressed in the same way as the corresponding form with -ate , if there is one (le ˈ gitimacy). Otherwise, the stem keeps its usual stress, though sometimes with a vowel change (su ˈ preme — su ˈ premacy). See also -cracy.
Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012