Simplify the following text for a Grade 18 native English-speaking person.
Original: Its membership comprises hundreds of music companies including all four `` major '' record companies ( Warner Music Group , EMI , Sony Music Entertainment , and Universal Music Group ) , associate members such as manufacturers and distributors , and hundreds of independent music companies representing literally thousands of labels .
Simplified: Its membership comprises hundreds of music companies including all four ` major ' record companies ( Warner Music Group , EMI , Sony BMG , and Universal Music Group ) , associate members such as manufacturers and distributors , and hundreds of independent music companies representing literally thousands of labels .