Each claim has a beginning date of Sunday. It may be the Sunday of the week in which the layoff occurs or the following Sunday, depending on the last day worked. Generally speaking, if your employee's last day to work was a Monday, Tuesday, or Wednesday the claim will likely begin on the prior Sunday. If your employee's last day to work was a Thursday or Friday, the claim will likely begin on the following Sunday.
Please discuss this with the mass layoff coordinator, who will give you the definite date. This may clear up any question that you might have with regard to column 25 (Claim Week Earnings) on your record that you submit.