Form 5304-SIMPLE and 5305-SIMPLE setup variants of the IRS approved SIMPLE retirement plan. The difference? Form 5305 SIMPLE requires a designated financial institution and Form 5304-SIMPLE doesn’t. SIMPLE plans are for companies with a simple business . . . → Read More: Form 5304-SIMPLE or Form 5305-SIMPLE explained by a Form 8881 CPA | Credit for Small Employer Pension Plan