120 Day Mailing Requirement for Plans in Insurance Seperate Investment Accounts

[Guest Frank Jackson]

I am working with some clients and discovered that certain investments that are in SIAs/PSA require the insurance company to mail all finacial reports required to neede to complete the 5500 120 days after the end of the plan year. However, I am not finding that this is true for Mutual Fund/Registered Investments. Any reason why they were made exempt?