Simplify the following text for a Grade 14 native English-speaking person.
Original: In 1985 , Noble Affiliates started its subsidiary Noble Drilling Corporation to shareholders , and that company in turn went public by the early 1990s , and then became Noble Corporation , an S&P 500 company .
Simplified: In 1985 , Noble Affiliates spun off its subsidiary Noble Drilling Corporation to shareholders , and that company in turn went public by the early 1990s , and then became Noble Corporation , an S&P 500 company .