Historically, sponsors of qualified retirement plans (with the exception of 403(b) plans) have relied upon determination letters issued by the Internal Revenue Service (IRS) for assurance that their plans have been designed in compliance with applicable tax regulations, and accordingly, are qualified tax-exempt entities. While there never has been a legal requirement to obtain a determination letter, most plan sponsors preferred to obtain one because of the additional comfort provided that the plan, at the time the letter was issued, was designed in accordance with applicable tax regulations.