20 Miss. Code R. § 101-300-300.00
The effective date of an initial claim will be the Sunday preceding the date on which the individual files a claim for benefits by any method provided by the Agency. If the claim is filed on a Sunday, then the claim will be effective on the Sunday it is filed.
If the Agency determines that an individual filed their initial claim at the first available opportunity, the effective date of the claim will be the Sunday prior to the date they became unemployed.
An initial claim for benefits may be backdated to the Sunday proceeding the date the individual became unemployed provided good cause is established, and the individual reports within seven (7) calendar days of the date the first opportunity was afforded by the Agency.
Good cause will be defined as circumstances beyond the control of the person. For the purposes of this paragraph, the first day of unemployment for an individual whose unemployment begins on Saturday or Sunday shall be the following Monday.
In case of a catastrophic occurrence, the Agency will have the authority to waive the time afforded the applicant to file a claim.
20 Miss. Code. R. § 101-300-300.00