Jane

I am not an expert in Form 5500 but I am very curious about one question here: I thought all large groups (>50 enrollees) are experience-rated to some extent (premiums depending on their past claims). But why most Form 5500 Schedule A filings are nonexperience-rated? Is this an option that employers can choose? If yes, what kind of employers are more likely to file as nonexperience-rated? Thanks!